Set a timer, grab a bag, and fill it. If you have 5 minutes or 15, set your timer, grab a bag, and run around the house filling it with things that can be tossed, donated, or put away. Move quickly, turn off any distractions and quickly clear any flat surfaces of clutter. Depending on the time you have for this task and the clutter at hand, you might be able to move through your whole house or you might not get away from your kitchen table.
Gathered Bag tutorial: there's a free pdf file on her page with the pattern pieces AND she has some different possible variations for the bag with bows and such. Super cute. Wouldn't be too hard to use for a diaper bag either.