Wood decks require regular inspection maintenance to make sure they stay in good structural condition. The first thing to do is check around for any structural weaknesses that require repair or replacement. Any rotted wood should be repaired right away.
Loose nails found popping up above the floorboard surface should be pulled and replaced with deck screws (easily done with an inexpensive attachment for your power drill).
If any severely cracked decks boards are discovered, these can be removed and flipped upside down. Since the underside of the board hasn't been exposed to the sun, it is very likely in almost as good a shape as it was when the deck was first built.
Finally, give your wood deck a good spring cleaning with a homemade solution of three quarts water, one quart bleach, and a half cup of ammonia-free detergent (careful: mixing ammonia and bleach can form a dangerous gas). Apply the mixture to the deck with a stiff floor brush and let it sit for a few minutes, then rinse thoroughly.
Now you and your wood deck are ready for a season of sunshine!