Clean out fridge, work on emptying freezer in case of power outages.
Turn down the hot water heater and unplug large appliances so they don't drain power, like the TV, washer/dryer etc.
Make sure all laundry is done and put away.
Buy a light timer for a living room lamp to turn on in evenings so it looks like someone is home.
Stop mail for delivery.
Ask a neighbor to check your porch a couple times a week to make sure mailers and catalogs don't get left on the porch.
Stop milk delivery.
Prepay any bills that will come due.
Mow grass or rake leaves, if needed. Arrange for a neighbor to do same one/two times while gone, or shovel walks as needed.
Can't think of any others off hand.