Was gonna say exactly this. Doing something small and actually accomplishing makes a huge difference because it tells your brain I am capable of doing things. From there it becomes easier to slowly raise the bar of what your brain thinks is doable and thus things that you'll psychologically be able to go ahead and do.

It's really important also to make sure you don't aim for things that are too hard and fail too often. A bit of failure is okay but if your ratio of failure to success too low you'll lose self confidence and it becomes harder to get into a sort of "flow" of progress.