My first class is just two days away now with "Yes You Can Paint" in Cincinnati. Bob introduced the filbert brush to me and rocks too. Not being artistic, and new to painting, I'm not feeling perspectives, which lines to follow, say in grass, when to change them, when not to. There is much to learn.
Practice, practice, practice. It isn't just the rock, it is making it look like it is IN the water and not floating on the water. And my water lines, I didn't think about which way the water was flowing until later.
I like this painting though and had fun. The original appears more vivid, especially more green in the water.