Seal all cracks with caulk. Inside and outside. If you get a chance to paint... the prep work often involves wiping and dusting off the cobwebs. If you aren't painting, you may want to wash the walls. Get the carpets steam cleaned. Scrub out the kitchen cabinets and lay down fresh shelf paper. Be sure to seal any holes you may notice. Wipe out all closets and shelves in a similar fashion looking for traces of bugs or rodents. Spray with a lavender oil when you finish. Bugs and rodents don't like that smell at all.
Outside make sure no greenery touches the house. Make sure the vent holes to basements and crawlspaces have proper screening. You can also lay down a line of diatomaceous earth or boric acid around the perimeter of your home. Both of these are harmless to people and pets but bad for bugs.
If you are painting the exterior of a new home... the painter can add an insecticide to the paint. I haven't felt the need to do this in Oregon... but when I lived in Georgia, it seemed necessary. The South grows big bugs.
http://en.wikipedia.org/wiki/Diatomaceous_earth
Good luck.