If it's any help, I tend to take 1 of 2 approaches to creating a character:
1. See what's already out there, and create my own homage/interpretation or put a new spin on an older/existing idea.
2. Find a particular color combination or a chest+legs combination that jumps out at me, then build a character up from there.
For an example of 2, I really like how the retro sci-fi armored top goes with the justice pants, (regular), and have built several characters off of those 2 pieces alone, (see example here).