Wood decks are generally built on a foundation and frame. To get the most servicable years out of a deck, it needs sufficient ventillation.  Check to see that your deck has vents around the skirt.  Air needs to circulate underneath the wood deck to keep it dry so that mold and dryrot cannot grow and eat away at the structure or the decking.

Also, the decking itself needs proper maintenance.  If your decking is nailed to the frame or understructure, sometimes the nails can losen and pop up.  Make sure to hammer the nails back in when this happens.  Screws are a better way to secure decking to the frame.  If your decking is nailed down, you can remove the nails and screw the deck boards into place instead.

Sometimes deck boards twist and warp.  They can simply be replaced when this happens.

As I mentioned in the beginning, wood decks need to be protected from moisture, both underneath the deck and the decking and railings themselves.  Apply a water-proof or water-resistant sealant to your deck and railing every season.  This will keep out damaging moisture and give your deck a longer life as well as keep it looking good for your backyard parties adn barbeques!