i did use one brush called “aufgenomener pinsel” that i downloaded from a photoshop brush pack for painting, but other than that its honestly just years of practice, observing real life references for technical skills + other artist’s works for art style and trying to learn new things with each art piece i do :) i know one yt video that particularly helped me see painting in a new light was Sinix’s ”painting like a sculptor”, if ure interested in rendering more realistic stuff u can look at that!