Edit: Aside from achievements.

Please tell me how Mages and Hunters self-heal.

I heal my mage via a glyph. Not sure what hunters would do.

@ draken, mend pet, since it's the pet that's supposed to be the one taking the damage

Evocation glyphed heals you for as much mana as you gain. It's probably the best glyph for leveling a mage ;)

You only need to work on first aid if you do a lot of extreme leveling or PvP.

@Drakkenfyre: Mages self heal from the glyph of evocation, a glyph that I highly recommend all mages getting. Hunters self heal either through mend pet (if you count your pet as self healing) or through chimera shot. I realize that not all hunters have chimera shot, but keep in mind that MoarHeroisms' question just said "capable" of self healing.

@Noyou: Glyph of evocation doesn't heal for the same amount as it restores, though it used to. Blizz deemed that OP and cut it down to 40% of maximum health.

You guys all forgot Spirit Bond.

Yes, I did forget the Glyph. And no, I don't count pet healing as self-healing. And one Talent I wouldn't consider a class "ability" to heal on the order of what the OP said since it is indeed a Talent, and only one spec can get it.

Harvoc, not everyone got Spirit Bond because it had one major flaw. The self-healing kept being cast even when you were at full health. The heal was considered a normal heal, and gained threat. So you could stand there, doing nothing, and gain threat from it. If you had a good tank this didn't mean much, but the fact is it still acted like a ticking threat accumulation just watching the boss. If they haven't changed it since then, it may still act this way. Altho the tanking changes made probably make it a moot point now.

Let's not forget that Evocation is on a 4 minute cooldown (2 for Arcane).

"Please tell me how Mages and Hunters self-heal."

Eat&Drink during combat

busuan, in the chance that you are being serious, that ability was removed, long ago.

Towards the end of Burning Cruasade, bosses were changed to emit "aggro pulses", which kept you in combat constantly. You could no longer use Invisibility, run away, or Feign Death, and eat/drink.