The standard stroke, which is the way your brush marks are laid down, is a series of dots that are close together to make a line, but click the icon below the Brush icon (named Dots by default) and you can choose from a few others. Choose Spray and draw another mark on your object. Click and drag off the mesh to orbit round to an unmarked area.
The Spray stroke type is great for more organic sculpting, with some natural chaos. Adjusting the Brush size by pressing Space results in different looks, because the spray scales with the brush size. If you need more definition, go to the Geometry section on the right and click Divide. (We’ll talk more about this in future issues.)