I begin with the front of the bot.
I try many cosmetic parts untill I find one that i like, when I am happy with the front I start building arond it.
I add a hover blade in the middle, you can add anything you like in the middle, perhaps a module if you want
I try what cosmetic parts would look good, when I am happy with one I start to build around it
4. Main body
I add more cosmetics to the main body and if possible I add rods to hold the wings
For me the tail is the hardest part of the bot to get to look good, I add a warp drive Engine using the League badges to my copters, but that is something that is just for fun.
I add guns mostly to the front of my copter because usually I shoot only things that are in front of me
I add rotorblades and thrusters to the copter
I change small things, add vapourtrails and flags and I paint the bot