1) Check your roofing every year for damage. Any missing shingles, discoloration, or problems with flashing need to be repaired by a roofing professional immediately.
2) Make sure you don't have any trees hanging over your roofing. If the tree falls it will cause expensive damage to your roofing and building.
3) Check your attic and crawl spaces for any leaks coming from the roof.
4) Clean your gutters regularly to prevent ice damming in the winter and maintain proper water flow.
5) Make sure your roofing vents are clean and clear of obstructions that would prevent your roofing from breathing properly.