As you work on things or change things you will frequently have to disconnect a lot of cables. It can be confusing or a pain to remember exactly where everything connects back in.
Get yourself a pot of nail polish, brightly colored and a pack of toothpicks and use the toothpick to put marks where you need them. In fact, whether you are building quads or repairing your Aston Martin, you should ALWAYS have nail polish and toothpicks in any well stocked toolkit; you'll be amazed how handy they are.
For motor cables into your FC, for example, you can use dots to mark channel number (As in the pic below) and this is a lot easier than trying to write the number really small with a marker or such.
For other connections, take the toothpick and run a line from one side of a connection to another so you have a quick visual reference - line up the marks and voila!!
Comments
I had to do a double take when I saw your photo - it looks like my stuff! :) I've been thieving the wife's paint for a while now :) Works great!
Its a good tip. When taking stuff apart and putting it back together, it is also a good idea to take some photos before you start and as you proceed and make notes and drawings too if necessary.
And a final check 2 or 3 times with a voltmeter for short circuits