>>176806 (OP)
I like to use drawn references, so I generally use one of two approaches.
>1. Have a broad character concept/archetype in mind first
Lower your expectations and begin to dig through boorus with applicable tags. For example, what if you want a scientist/doctor-type woman? "labcoat -male_focus" on gelbooru or sankaku. No matter what, be steadily adding exclusion terms if there's a lot of certain canons you don't want to use the appearance of (in this case, Tae Takemi is very plentiful), or refining terms such as hair or eye color to narrow it down as you get a better idea.
>2. Find art first
Dig through boorus the same way as described above, find an image set, and build a character around it. For example, I could throw together an edgy, uppity delinquent boy or something from this random-but-half-ass-consistent collection of images I pulled from Hirota Tsuu's artist tag.
No matter what, consistency is key. Don't worry about meeting a quota of pornographic images or having a certain number. Just worry about what the characters in your images look like. Mix and match artists, not features. If you only Also just use your judgment when deciding whether or not to use a canon character as a faceclaim as the first Anon described. A character from a Deep-Sea Prisoner or Miwasiba game might be fine because I'm pretty sure there's two people actually into either of those creators and I'm one of them.