>>6791337#1- Stop being afraid to cut into your kit and fuck up.
#2 - Once you complete #1 then learn to chop off existing pegs and balljoint in order to glue different ones into place. Or just glue them in other areas.
#3 - Putty gaps, sand, prime, cry in frustration, putty, sand, prime, cry again, repeat until you don't see gaps, seams, or uneven bits anymore.
With that you can pretty much attach anything to anything else which is a good place to start.