This may be very common sense for many people, but I know there are some that haven't tought of this, so I tought I should post it
So when you a leveling your character (questing, grinding whatever), you can easily join a bg (preferably AV) and get full buffs from other people before the bg begins. And when you got the buffs you want, you can just leave and return to your leveling
The only minus is that you will get a 15 min debuff (Deserter) which will stop you from joining a bg again for 15 min. But after this debuff is gone, you can rejoin and refresh your buffs as you like