It’s also helpful to know where the standing waves in your microwave are. Put a layer of shredded cheese on a big tortilla (so you can eat it and it’s not a waste) and run it till it melts the cheese. Observe where the cheese is melted and not melted. Put your coffee cup along the same band of melting. That makes your heating more consistent. Fortunately, mine has it’s strongest focal point dead center (which, I suppose, is not a surprise from a design perspective… still good to know).