I used regular acrylic craft paint since I have many colors available. Acrylic paints dry rapidly, and are my art media of choice. You will need brushes, of course, and you can use liners, rounds, flats, shaders, etc. I use the liner brush for fine details.
Now the fun part begins! Using your painting skills, paint your pet picture on the rock. Pay attention especially to the eyes, as they can make the entire picture/sketch.