Brush tool is a excellent tool (treat tool) in Photoshop, it helps you to make abstractive pictures. I will show you a picture that i make it by brush tool, but it is not a cool picture at all. I create this picture because in my country, next time is autumn season. I think it is a lonely season :(!!!
I think everyone can do it....!!!!!
Firstly, you have to download some beautiful brushes on internet and put them into Brushes folder.
Next, i took sky by digital still camera and use tool Black/White to make the background color to become yellow.
NOW, open your mind and do some crazy things....;))!!!!