1. Ganking vs. Camping vs. World PvP
I define ganking as the act of killing a player who is at a severe disadvantage. Typically this means level difference, but I also include gear and spec considerations, and situational considerations (killing a player that's fighting a mob and low on health). Basically, I consider ganking to be killing someone in a dishonorable fashion. If the ganker hangs around and repeatedly kills you when you rez, that's camping. If a similarly-leveled member of the opposite faction engages you in a bout of PvP combat, kills you and goes about his merry way, that's world PvP. I've seen these three terms used interchangably so many times, but there really is a difference.
This is geared more towards lowbies and new players. On our PvP server, any zone outside of the major cities and starting zones is contested territory, meaning horde can attack you there. But not all contested territories are equal! Where you choose to quest will have an impact on what kind of horde opposition you can expect. Areas with a strong goblin presence and neutral questgivers mean that you'll be in very close proximity to enemy players. Ratchet, Stranglethorn Vale, Tanaris, Winterspring, Area 52 and countless other little quest hubs are open to both factions. Hillsbrad Foothills has traditionally been a prime spot for PvP and the folks who routinely raid Southshore aren't afraid to cut down any lowbie they see, though that's changed now. Ask around if you're unsure where you should level.
For the lowbies, Redridge Mountains and Duskwood offer few, if any, quests for horde players, so the only hostilities you'll encounter there are folks occassionally causing a ruckus in Lakeshire or Darkshire. I've found that Desolace truly lives up to its namesake as well, and Felwood isn't too bad these days. With the introduction of Wrath of the Lich King, Outland is nowhere near as populated as it once was, and I still find places like Zangarmarsh and Blade's Edge Mountains to be the easiest leveling zones of them all. Similarly, Howling Fjord doesn't see as much traffic as Borean Tundra on account of both sides having to go a little farther out of their way to get there.
3. Know Your Surroundings
This is the #1 rule to avoid getting killed. Always, always keep an eye on your surroundings. Before heading into a quest area, scout it out; a task made far easier if you have a flying mount. If there seems to be a lot of horde questing there too, go find another quest to do while they finish up. If you're fighting mobs, spin the camera around every once in a while to make sure no one's sneaking up behind you. If you see a red name, it's a good idea to err on the side of caution and move elsewhere, so you can safely assess the situation from afar. Hunters and druids, make the most out of your ability to track humanoids, though higher-level players have access to buff foods that provide the same benefit.
4. You Just Got Killed, Now What?
Maybe you got ganked, or maybe a scrub just caught you off guard. You released and made your way back to your corpse. Do not hit that accept button! Too many people think they can rez on top of their corpse, buff and sit down to eat and drink. If you do that, you're just asking for a camping. Take the opportunity to examine your surroundings before proceeding. Is the ganker still around? Is he questing, or does it look like he's waiting for you? Does he have friends? If you got killed by a player with stealth, you can reveal their location by moving close to them in ghost form. Spend a minute searching the area immediately around your corpse, especially the high ground and prime lookout spots.
Then rez behind a tree. I know, kind of counter-intuitive isn't it? But it does work. Use your surroundings to your advantage; trees, pillars, big rocks, bushes... they all serve the same purpose. If you're in a multi-storied building, you might be able to rez on a different floor. If you can put an obstacle between yourself and your attacker, it increases your chances of getting away, and that's really your top priority at this point. If you suspect your assailant intends to camp, don't stick around.