It's a pretty common figure of speech.
What I can offer for advice is, start with a backstory first then a description and go from there. You should try to match your OC's colors to what kind of "universe" it is in (Meaning dark, happy go lucky, etc.) so if you want it to be a OC in a pretty kid-friendly environment try to keep from the darker colors and go for something more eye catching but not like neon. A good backstory is the best bet for starting your character.