Use standard brushes
Contradicting my earlier Pro Secret, I feel that there’s too much emphasis on brushes. I used the stock Photoshop brushes for the first 10 years of my career, mostly because Photoshop didn’t have custom brushes. A lot of people have even said to me they liked my work better when I just used the Round brushes. I use the stock brushes all the time, and when I’m having trouble or trying to learn, I use the simplest brushes I can.
There are so many variables in painting, so do everything you can to simplify what could be causing you trouble. Custom brushes poorly used can make your work much more difficult. Fancy edges and textures won’t hide a lack of understanding in the art basics.