To suggest movement or attract your reader's attention to the main aspect of your drawing: just draw lines!
Start off with the help of a ruler. With practice and good control, you can draw freehand lines.
They go in the background, such as, for example, around a character that's running. They need to be horizontal, tapered (that is, ending in a point) and parallel to one another. The closer the lines are together, the faster the suggested movement.
Step 1: ruler
Step 2: drawing
you can use whichever instrument you prefer: ball-point pen or pen. If you use a pen, be careful with the amount of ink! Too much ink: the line will not be sharp enough. Not enough ink: the line will be broken.
They allow you to draw attention to a character, his face, an object, etc.
Step 1: determining the point of convergence
Step 2: doing the drawing