How am I able to hit high in pvp?

Im a night elf, and as i go through pvp, i see many players that are able to hit very high. For most, 200's and 300's might be a very small amount of your hp, but in lower levels (10-14) thats almost all of your hp. Anyone know how they are able to hit so high? (and i know its not just the equipment they are using because mages and warlocks can hit that high too, with their spells)