Make the outside of your house look clean. Get rid of stained and dirty concrete driveways and patios. You can rent a pressure washer from a rental company or if a friend has one borrow it for a weekend. Remember different size pressure washers and different tips have have a stronger and weaker spray. When using one for the first time you need to test it out on an area that wont be noticed and hold it a couple of feet away from what you are spraying off. A pressure washer can damage and tear up surfaces if held too close.
Seal it up: Caulk and seal around exterior door and window frames. Look for gaps where pipes or wiring enter the home and caulk or use expanding foam to seal them up. Not only does heat escape from these openings, but water can enter and may eventually cause structural damage and mold problems.