This tip is from Gramma. She's done laundry for longer than the rest of us have been alive...starting with fish-slimy clothes scrubbed in a bucket (her brothers and father ran a fishing business in the Mississippi), and ending with a nice washer and dryer set.
She puts a couple of big bath towels (dry ones) in the dryer when drying small loads. This speeds the drying process and saves electricity and $$.
Aunt Chris vouches for the effectiveness of the towels.