Making dashed and dotted lines
Changing a couple of settings in the Brushes palette enables you to create dashed and dotted lines with ease. In the Brush Tip Shape pane, increase Spacing to a value higher than 100% to separate the individual imprints of the brush tip (the brush tip instances). Switch to the Shape Dynamics pane and select Direction from the Angle Jitter pop-up menu. For best results, make a selection and choose Edit => Stroke to apply your dotted or dashed brush along the selection border.