It can be tough when you have problems with anatomy. I've been there. If you've got serious skill shortfalls, then trying to push yourself into things you can't do might lead to frustration and discouragement, and that's no good. One thing you can do to improve is poke around on DA and find photos of things you don't draw well--hands, backs, whatever--and sketch and doodle from them. It might be dishonest to post work you've copied, but there's nothing wrong with doing it for practice.
And there's nothing wrong with photo references. Professional artists use them all the time.
On the other hand, avoiding things because you lack confidence will inhibit your growth as an artist. One of the things this tutorial has done for me is push me to draw things I might not have tried otherwise. Why I try, I often find that I've got the ability in me after all...and if I don't, then at least I know what I need to work on. If I find strong inspiration, then it gives me the motivation to improve on the areas I need in order to come back and finish the picture.