Most people don't mind clutter, but not the grime and dirt. Wipe off surfaces in your kitchen and bathrooms as that is where most of your guest will be. If you have dirty dishes in the sink just put them in the dishwasher or if you don't have a dishwasher put them in the oven. And if you have carpet just a quick vacuum in the high traffic areas will work.
A little clutter is ok, but if you are like me I don't like lots of clutter. To take care of some of the clutter just work on the "clutter collection sites". You know the ones.....junk mail on the table, shoes in the entry way, etc. Get a large laundry basket and put all these "clutter piles" in it and hide the basket in a closet. That way they will be all in one spot and you will have less to deal with later.
Nice smelling scents always makes your home feel much better. I use candles in the winter, but summertime just doesn't seem like the time to have candles out so here are a few other ones. You can put a drop of lemon-scented oil on light blubs before you turn them on. You can also tuck scented fabric softener sheets under couch cushions or inside throw pillows.
This should help you speed through getting ready for those last minutes guest that love to appear at your door in "just a few minutes". :)