In case anyone is ever worried that you are cheating, my tweet has over 1k replies of other artists saying that they do this too. Tracing over reference pictures is a fine way to learn. Sketching over reference pictures is completely fine. Frankensteining reference images together is fine. There are both professionals and novices saying that they do this too.

Use your resources. There’s no shame in it! I’ve been a professional concept artist for over five years now and we do this all the time.