What you need:
Flying mount, character with ranged damaging abilities.
Begin before the WG starts (like 2-3 mins left). Or players may come on their flyers and rape you.
Mount up and fly on a gate or a structure in WG (find a place you won't fall off, a place where you can reach a turret, where you can reach a place where players walk, a place where you can go out of LoS from Catapult fire or enemy casters on ground, a place that will be near the field of battle, like main gates, so you get rank faster).
Dis-mount before the battle, make yourself comfortable, look around, so if you don't like the place you can go find a new one.
When the battle begins, destroy the turrets. Now you can either continiue standing there and try to kill enemy players, slack there getting counter for kills so you get rank, or jump down and go get a venichle or something. Good to combine with the other WG trick that lets you get Lietenant at the start of battle, so you can get a venichle and rape the gates without getting fire from turrets.
Here's a pic: