Using references is not cheating. I know this because four years of formal education in visual arts—we had to use our sketch books to show our artistic processes for our "actual" pieces and that we were practicing the skills they taught us. Sketching from live models was strongly preferred, since that made it easier to get a more convincingly shaded picture, but using photos was allowed when that wasn't feasible(i. e. wild animals, luxury vehicles, historical figures). If you didn't use references, your work would turn out weaker, your sketchbook would be flatter, and your teacher would give you the "I know you can do better than this" speech at sketchbook review.
So, if you're bad at hands or feet, practice drawing your own—fifty times, if you have to. If you have trouble with space or scenery, draw the room you're in (vanishing points! composition! scale!). Look up the stuff you want to draw. There are ways to cheat at art, but using references isn't one of them.
