Suspense is the tension that is created when you are waiting for something to happen. You might be waiting for news of a loved one; you might be waiting to see if the creak on the stair which sounded suspiciously like a footfall sounds again; you might be waiting, lottery ticket in hand, to see if your numbers have come up. Often, it’s a period of magnified inactivity which anticipates a moment of action.
What interests me about suspense, which is often so gripping for your reader, is that it usually occurs when nothing is actually happening.
If this is a contradiction that you’d like to explore further in your work, why not write a scene in which nothing at all takes place, but the tension is excruciating?