Write each step as an event rather than a specific scene. In other words, each step is made of a set of scenes. This will help keep you out of the story details prematurely.
Keep your steps short and to the point. A step should ideally be only one to two paragraphs. If you have an idea for a characterization or a piece of dialogue, go ahead and include it in the step, but keep it succinct.
Capitalize your characters' names and the props the same as in full screenplay format.
Format the step outline for a short film to include the slug lines or scene headings above each step. In a 10-minute film, this will make drafting the finished script progress much more quickly.