When doing "big" laundry -- think comforters, blankets, sheets -- throw some tennis balls in the dryer with those items. The tennis balls roll around with your laundry, fluffing it up and keeping it from getting tangled up. It also makes your laundry dry more evenly and quickly.
Bonus tip: the tennis balls work great for working out lumps in down-stuffed comforters and pillows. Toss in the dryer and fluff for 30 minutes -- the tennis balls "massage" out the lumps!