Several classes have skills, abilities or cool-downs that will help them level. And for 70 levels, these things have belonged exclusively to the player to use, abuse, misuse or forget to use at his or her leisure.
However, with your entry into the world of raiding, you should definitely get out of the mindset that these abilities intrinsic to your class are yours. Most raid-leaders definitely believe these choices are not yours to make but belong instead to the raid. Here's a short list:
Soul stones: While it's nice to be able to self-resurrect after a bad pull, in Karazhan and beyond your soul stones no longer belong to you. The raid leader should indicate who should be soul-stoned. Remind the raid leader when the cool-down is up as he or she may wish to change the target.
Battle resurrection: Druids, please do NOT use your resurrection if there's anyone else available to do it. Since yours is on a longish cool down, it's better to have that available to fix a set of unfortunate circumstances on a boss.
Pets: Hunters and warlocks may be expected to sacrifice pets to achieve a particular goal. While not true for hunters, warlocks are often expected to summon a pet to fit the current fight. Don't get attached to your imp!
Divine Intervention: I'm listing this only for completeness. Most paladins aren't in the habit of using this except to prevent a wipe. Since the target of the DI is immaterial (as long as he or she can resurrect the rest of the raid), you should just be ready to pop it on anyone who can rez that's in range.
Enervate: If you're a restoration druid, your enervate may actually still belong to you. However, if you're feral or moonkin, please do not use your enervate until the raid leader calls it out. He or she may be relying on that enervate landing when it's called for. So don't use it unless asked for.
Self-resurrection: This applies both to a recipient of a soul stone and shaman using an ankh. You should likely know whether you're meant to use the resurrection upon death or if you are to quickly get the raid back up after wiping. So make sure you're not wasting the chance by resurrecting before you should.
That's about it. If you keep these things in mind, it'll help you not look like a n00b and keep the raid leader getting what he or she expects. Good luck in your raid!!