Clean the gutters and make sure the downspouts are running freely.
Remove ivy from house, it is a termite conduit and destroys the mortar between the bricks
Put bleach down the floor drains in the basement, it prevents bugs and sewer gas from entering the home
Paint all exterior flaking paint
Make sure the storm windows are in the closed position for winter. Make sure that the screens have no holes in them for summer.
Make sure the the baffles in the ductwork in the basement are in the correct position, for winter or for summer.