Familiarize yourself with the zone and all the structures. Some building are capturable, others are destructible, and others can be captured or destroyed.
Here are a few tips when playing Wintergrasp offense. The main idea is to hit the keep hard with siege vehicles.
If your faction is defending Wintergrasp, remember that the best defense is a good offense. Destroy enemy workshops and man the cannons.
There are a number of tools you can use to win the battle, from rocket launchers to full-on tanks.
Flying machines and goblin shredders were announced at the Worldwide Invitational but have yet to make it to the live realms. Let's keep our fingers crossed, hoping to see more mayhem!
Aside from quests directly related to the battle, there is a daily collection quest that requires players to get drops from other players and elementals.
Speaking of elementals, Wintergrasp is the best place in Northrend to farm for elements. Players controlling the zone can 'see' greater elementals that drop 1-3 crystallized elements 100% of the time.
One of the more difficult Achievements in Wintergrasp is to slay 10 enemy players in several areas in the zone. Here's a map to generally show where each area is. The hard part then is actually finding players to kill.