I'm not a professional quad builder, lol I bought and flew countless store bought premade cheap drones. I always been into the drone racing and building, but always got overwhelmed when I began to attempt to build one, I done a lot of research and watched countless videos, finally I took the plunge, here is my story and some amateur tips that may help you...
some things to think about...
What kind of R/C multi rotor you would like to build (3 to 8+) props and motors, obviously the more rotors the more expensive.
What kind of features you are looking to have (gps, Bluetooth, etc...)
What style or size, meaning you can have a large 4 rotorcraft to have all the nice features like auto pilot and mission planning or you can have a small 180mm to 240mm 4 rotor racing quad.
If you want to race FPV (first person view) or just fly line of sight. You can always start with line of sight and upgrade to a FPV multirotor later for budget and experience reasons.
If you want to focus on photography or speed and agility, photography will be more of a investment mainly because the camera gear, and size of the drone you need to build to have more features and stability, don't get me wrong a lot of pilots create amazing videos with small racing drones, but most are mainly freestyle videos, with a little larger multi rotor you would be able the mount a pan and tilt camera mount that is controllable with your transmitter or a co pilot or even your phone.
If you haven't seen my page on commonly used terms and abbreviations check it out.
Next... DO NOT OVERTHINK IT!!! lol This is what kept me from building for soooo long, it really is pretty simple, and there is loads of information online to help, the multi rotor community is awesome everyone I mean everyone will do what they can to help you, really is a awesome community and makes me proud to be human because these people are so into the hobby they want to share the experience with everyone, I mean what human hasn't thought about flying at least once lol
PARTS LIST:
FRAME: depends on the features and type of multirotor you want.
MOTORS: again how many and how large depends on the type.
ESC: Electric Speed Controllers, one for each motor (more on that later)
FLIGHT CONTROLLER: (more on this later)
POWER DISTRIBUTION BOARD: (different features, more later)
TRANSMITTER and RECEIVER: (again more on my experience later)
CAMERA: FPV and/or Photography
VIDEO TRANSMITTER: (only if flying FPV)
FPV GOGGLES: (again only if flying FPV)
LIPO BATTERIES: (more later)
LIPO BATTERY CHARGER: (more later)
PROPS: clockwise and counterclockwise, normally come it sets
Ok, now that we established a starting point, parts list and hopefully you have a little more understanding of what is needed and what type you want to build let's get a little further into each item and my experiences.
FRAME: I started with the crazepony H210, it's a small and stronger racing frame, I actually have purchased 2 of them, (first one lost in water and never found), when I first bought this frame my plan was to put all the features I could on it. I quickly learned that the frame is mainly focused on racing so it is tight for anything more than racing. It is a awesome starter frame and for the price you really should at least give it a try, you can always use the same guts (motor, escs, flight controller, etc..) on a bigger frame. This frame has held up to some gnarly crashes. (UPDATE: Crazepony no longer available posted a better alternative.)
MOTORS: How many? It's up to you and the frame you chose. I went with 4 of the EMAX RS2205 2300KV, honestly only because the reviews and what I seen online, remember I am no expert, and turns out when I meet with people, they said I have some "POWERHOUSES". I think to myself "OOO, YEA I DID SOMETHING RIGHT" lol. Don't over think the motors, one thing that had me hesitate is if the motors were designed to only spin a certain direction, well I couldn't find anything because it was so obvious. lol There is not a clockwise or counter clockwise motor, you can either physically switch 2 wires to change the direction or change inside a program named "BLHeli Suite" I used the windows versions which the UI (user Interface) looked like the 90s or a industrial process plant program, but it was actually pretty easy to figure out, even when i had problems and couldn't find answers online a little tinker was able to fix the issues (syncing escs, flashing escs, motor direction) as a beginner with new parts all you really might need to know now is changing motor direction. I'll talk about programs on another page, but you can find plenty info online to help.
UPDATE: You can now change the direction of the motors in Betaflight.
ELECTRIC SPEED CONTROLLERS: (ESCS) Again the quantity depends on the type of multi rotor you are building, You need 1 for each motor, I started with 4 Littlebee 20A mini. The ESCs job is to control the amount of power going to your motors straight from the battery, they have 4 wires on the input side and 3 on the output side ( 4 in 1 escs may vary) input has a positive and a negative that will go straight to the power distribution board and 2 smaller wires which is known as the signal wires, which are a positive and a negative, these wires go to the flight controller which allow the flight controller to tell the ESC how much power to give the motor which it decides, depending on your physical control inputs on your transmitter (your thumbs or fingers lol) or the processor on the flight controller. The 3 wires on the output go to the motor, these are the wires that if you switch 2 of them you're able to switch the motor spin direction. the ESCs come in a variety of different amps meaning how much power they can safely handle before they burn up or fail kinda like a fuse rating, don't get discouraged I kinda was lost for a little bit on this so I just got the 20a and I learned from other people that 20a is good unless your going to use a battery larger the 4s, more on the batteries later. I've tried a 4 in 1 ESC which has the same standard mounting hole size at your flight controller and power distribution board so you're able to stack them nice and neat, if one fails it kinda is more of a pain to replace and might be a little more expensive. On a stack you have to almost do a full teardown to get to it and unsolder all connections to it, on individual ESCs they are normally on the arms so only have to unsecure the esc and unsolder the 7 wires on the esc itself and replace only the faulty ESC.
FLIGHT CONTROLLER: My first Flight Controller was the Crazepony Afro Naze32, these are the brains of the craft, most have built in sensors like barometer, accelerometer, and compass. but I have learned that like a computer each sensor used takes power from the processor so, some lower end flight controllers, you can not enable all the features if that is what you are looking for, with that said the Naze32 was awesome for my first quad, I loved it, just for flying its great. just don't expect to be able to make a multicopter that's loaded with features. This is the controller that is currently in the bottom of a bayou in Louisiana, and it wasn't the flight controllers fault, it was mine and a build decision that I regret and learned from, there is many to chose from, some with different built in features, some are designed to stack right on top of a 4 in 1 so it eliminates a lot of soldering and saves space, just really depends on what you're looking for and the options or features you want and budget of coarse. I do not recommend getting the top of the line for your first build. glad I didn't because I lost my whole first build.
POWER DISTRIBUTION BOARD: (PDB) I went with the Matek Systems PDB XT60. When it comes to the PDB there is some features you can have. There are boards that have OSD, LED, buzzer, lost drone. It is all personal preference. To start just make sure you have one that has the correct output voltages. 3.3v, 5v, 12v, and VCC are the norm. most PDBs are compatible with any other components. One of my concerns was the mounting hole dimensions if it matched my flight controller and frame, I learned that most everything has the same mounting holes. I mounted lights and wired them straight to the battery pads (VCC). This PDB suited me well for my first and I was happy with it. It has enough ESC pads to build up to a 6 prop rotorcraft, which leaves you room to upgrade.
TRANSMITTER and RECEIVER: I went with the Flysky i10 2.4Ghz AFHDS2 10 Channel. setup and wiring was very simple, it supports iBUS which is all 10 channels through 1 signal wire. (iBUS is Flysky's SBUS equvilant) Features a very easy to use touch screen to set up the buttons. 1 thing I found is that the receiver that comes with this transmitter is very bulky, because it supports telemetry which most multi rotors do not use the sensor and extras that come with this set, it's mainly for servos and what not, things mostly for planes. Another downfall is that there is not a very large community for support and find solutions to fix issues. ( I am still trying to see if I can use a different receiver, can't find anything about it online), other then that the controller has suited me very well and I like it, when I upgrade I will keep it, to pass down to my kiddos :). It also has usb support to connect to a computer very easily, to fly on a simulator. I'll talk about them on another page.
FPV CAMERA: I went with RunCam Swift. It's small and easily mounts with the H210 frame, now need to use the mounting bracket that comes with the RunCam, as the carbon fiber side plates that come with the fame has holes for the RunCam to fit. Not using the metal mounting hardware that came with the cam cuts down on the weight. a little bit. The RunCam has a built in basic OSD for voltage, which is really all you need if you're building a racing drone. Wiring was pretty straight forward. The cam accepts 5-17v.
VIDEO TRANSMITTER: For my first build, I went with the Wolf Whoop T86, (guess wolf whoop no longer available but it was similar to the one above.) it features switchable power outputs, lower for if your flying with other people to reduce interference between the each other, and a higher 600mw for flying alone and a little further. *AMATURE TIP* When ordering a after market antenna (it is recommend) be sure to get the same connection, the above transmitter is a RP-SMA, so find the same connection type antenna. Also it might be a good idea just to find a SMA transmitter. they seem to be more popular with people i have met.
FPV GOGGLES: I'm the type of person that like to get the best bang for my buck. I went with the Crazepony FXT 5.8Ghz. Mainly because I was scared and wasn't ready to invest a lot of money into goggles and didn't even know if I'll be able to fly with goggles on. I caught these on sale and I like the fact that the screen is removable so you can fly FPV with having the goggles on your head. Set up was easy just power your drone with the transmitter wired up and hit the scan button on the goggles. The clip that holds the screen to the head bracket could be better as it sometimes don't hold it secure to the set. Other then that they are a decent starter set if you're like me and just want to test the water before you purchase a pair of FatSharks. (UPDATE, original no longer available added a cheap better alternative FATSHARK)
BATTERIES: There are sooo many different batteries to chose from. Different manufacturers, types, sizes, connections, ratings... I first started with the cheapest 3S batteries I found. No Battery last forever so I figured i'll start cheap and learn what will suit me best. The first batteries I ordered was the Turnigy 2200mAh 3S 20C. Mainly because the price, reviews and the mAh. I wanted to get the longest flight time I could. I wasn't really worried to much about speed. because I was sure anything I built was gonna be 10x faster than the store bought drones I own. These batteries have suited me well. I still use a couple today. I have also got some 4S Tattu 1800mAh. I will say i noticed a huge difference between 3S and 4S. If you're new to flying 3S will be a good start. Trust me. XT60 seems to be the standard in the connection types, I seen others converting all their connections to another, but to start I recommend just sticking with the XT60.
LiPO CHARGER: LiPO Batteries can be very dangerous if not charged and stored properly. Please follow all the safety recommendations. Be sure to get a trusted and safe battery charger/balancer. I went with the Ultra Power UP120AC Duo. The unit has many features, able to charge multiple batteries at a time, can charge and balance the cells. Very Simple to use just select the size and capacity of the battery you are charging and start. it shows how long it has been charging and has a audible tone when the cycle has been completed.
ALWAYS FOLLOW THE LIPO BATTERY AND CHARGING SAFETY RECOMMENDATIONS!!!
PROPS: Last but not least the Propellers. There is so many different, colors, types, manufactures, sizes, materials, etc.. I went with RAYCorp 5040 3-blade 5x5x3. It's all up to you on the colors and type, some people prefer the 2 blades, some prefer the 4 blades, I believe the people that prefer the 2 blade is cutting down on the most weight possible. it's all your personal preference and what you feel is better for you. Just start somewhere and try different things and see what you like, I went with 2 different colors to help with orientation while flying Line Of Sight. Just need to make sure you have the right amount of Clockwise and Counterclockwise props, depending on the number of rotors you decide to have on your multirotor.