STEP 1 - Choose a subject.
STEP 2 - Draw individual sketches of your subject as it changes through space and time. Abstract enough? Let me explain. Specifically, what I did for the above was choose my hand as a subject. I chose a movement to depict. I began with a closed palm, and turned my hand over, opened it, and closed it again. I did this within nine frames.
Animation as a general rule uses twelve to twenty-four frames a second. For a storyboard you do not need to animate all twenty-four frames. You want to give the general idea about the movement. Include how you are going to transition between scenes. Are you going to emulate the Paprika style dream space, where subjects and scenery seamlessly bleed into one another, or an Akira Kurosawa fade from treetop leaves to urban domestic scene? How will your frame behave? Maybe a Private Ryan Blair Witch Project shudder, or angelic, smooth Hollywood arcs. It's up to you. There is a lot to think about.