Finish projects: this will teach you how to set reasonable goals and expectations and how to break down large problems into smaller steps.
Whenever you are facing something you don't know how to do yet, recall a previous time you were faced with something you didn't know how to do and that you learned how to accomplish it and moved forward: this helps me a lot with blockers and imposter syndrome--it shifts my mentality from being lost and not knowing how to keep going to one of "I'm capable of learning, that's gotten me this far, and will continue to advance me."