If you have storm windows that are cracked or dirty, repair and clean them now — prior to autumn installation.
Find a couple of scrap sheets of plywood and set them aside. When the weatherman predicts a cold snap, set the boards against the exterior basement vents on whichever side of your house bears the brunt of your prevailing weather patterns. This bit of scrappiness could help prevent frozen pipes. Be sure to remove the boards once the weather warms up — those vents are there for a reason.
This is a good time to check the condition of insulation and see if you need more, especially if you live in an older home. You can purchase unbacked or loose-fill insulation if you are just beefing up what is already there. If you are adding batted insulation to a spot that has none, remember that the foil-backed side is the vapor barrier, and it must face the heated area.