a lot.
Get out of the house a lot, and NOT to where she lives. Work out at the gym, browse a bookstore, whatever.
Clean your house.
Develop a new hobby, or get back to an old one. (If one of them was
, you're already ahead of the game with Step 1.)
Avoid familiar favorite places that were for the two of you. Go make some new ones. Try a new restaurant, in a new part of town. Do something you liked to do that she never did. Or do something neither of you did, even something as simple as going to a museum or zoo or something.