Adjusting to the Cataclysm Style

With a focus on restoration druid
WotLK Style
What do I mean?
A largely triage style, where topping everyone off is priority.
Damage: Tanks get hit hard and can be two shotted in a matter of seconds. If dps isn't topped off before a certain big move, they will probably die.
Mana: Back when stats were different and abilities weren't a percentage of mana (and in most cases, less expensive), mana was not a huge concern unless you were severely undergeared.

The Shattering and Cataclysm
Blizzard's main goal was to revamp the way people raided in Cataclysm. Dps had to watch threat more. Tanks had to work harder to generate threat. We had to CC in dungeons.
For healers, we now had to watch our mana. Before, when triage style was all about keeping tanks and dps topped off, mana couldn't be a huge concern or else raids would fail. Now, where damage isn't as urgent (at least in most cases) healing isn't about fast, quick heals. It's about mana conservation and survival.

How can you adjust?
More like, how did I adjust. There are a couple habits that have to be broken, especially as a restoration druid.
1.) Keeping everyone topped off.
This is the major one. Every healing class has to break this habit because we all were pushed to do it in WotLK. There are many reasons why we shouldn't, and can't do this.
    a. Spells are expensive. I've noticed that every class has similar types of spells with similar mana costs, so there's a basic style that Blizzard wants everyone to follow, despite what class you play. (Example: Nourish, Holy Light, and Heal (Druid/Pally/Priest) all have long casts times, heal for a very small amount and cost very little)
    b. Damage is distributed much more differently. While there are still times when you can't let people fall too low, there aren't any times when damage, outside of the tank, is going to one shot the player if they aren't topped off (and if it will, it is avoidable). Even tanks aren't going to get one shotted anymore, although they will be taking constant damage and will need the most healing (understandably).

2.) Blanketing everyone with Rejuvenation. (Or a bubble)
As a druid, and a disc priest, we were in a mindset of being prepared for incoming damage. Rejuvenation is an expensive spell to be used as a damage reflector. I've always been very against Rejuvenation blanketing because it is NOT a shield. But a lot of raiding styles in WotLK did encourage Rejuvenation blanketing in the same way a bubble was used. Now, in Cataclysm, it is even more apparent that Rejuvenation is NOT a bubble and should not be blanketed on the raid.

3.) Overhealing doesn't really matter.
Mana matters again; thus so does avoiding overhealing. I will address this more below.

Adjusting Strategies
1.) Know your spells.
This seems kind of obvious, but I mean really know your spells. Know the approximate mana cost, how much it will heal, how long it will take, and for druids, how much the HoT will do. Healing is much more calculating then it used to be.   
2.) Know your stats.
Along with number one, the best way to create a strategy is to understand your mana combat regen. Example: My Nourish costs approximately half the amount of my combat mana regen, which is every 5 seconds. Nourish takes about 2.1 seconds to cast. So by the time I've casted two Nourish, I've almost regen'd a good amount of that mana back.
3.) Create a strategy on how you will react to certain situations.
If you have to, and what I have done to help with adjusting to the new style, is place a health percentage with which spell I use on a dps.
-For example: If someone is 60% or lower, I use Rejuvenation.
 Assuming that dps is doing their job by avoiding unnecessary damage, a Rejuvenation should be enough to bring them up higher, and also gives a boost to any Nourish I may throw on them.
-If more than one person is below 70%, I use Wild Growth.
Because Rejuvenation is fairly expensive (right now, it's 16%; it will be changed to 20%) if more than one person is damage by a decent amount (70% is what I find to be good) Wild Growth is cheaper then 2 or more Rejuvenations. If it hits the tank as well, that's another HoT influenced by Symbiosis (Mastery) and helps boost Nourish.
4.) Overhealing and Cross-healing Awareness
As a druid, I hated my tendency to overheal. Because of the way healing was in WotLK, we didn't really do healing assignments outside of saving a big lazy green dragon. Because I'm a druid and my HoTs are "healing over time," I usually got the highest overhealing because some pally or priest was topping off damage that I was patiently waiting to heal up. This is my biggest complaint as a druid in Cataclysm, but healing assignments are back and should be used to not only lower overhealing, but also cross-healing.
A way to help mitigate this without having to stay with strict healing assignments is to add onto your healing/raid bars a indication that someone has a HoT or bubble on them. Incoming healing on Vuhdo or Healbot can be misleading because HoTs have a weird way of showing it. I sometimes feel like I should ask my healing buddies to add HoT indicators for Rejuvenation (at least) so they don't waste some mana on something I could've easily healed up.

Basic Healing 101
1.) Stand in the "insert color here" circle.
Range has increased in importance in Cataclysm. And I don't just mean being in range of the healer. All healing classes now have a healing aoe spell that is based off of a range that is pretty specific. For druids, priests and shamans, this comes in the form of visual effects. See those circles on the ground that glow and look pretty. Yeah. Stand in them.
As a healer, that means being aware of the raiders around you, even more so then normal. See a tank getting hit hard, and melee taking some splash damage. Use Swiftmend to proc Efflorescence.
That being said, it might be wise to let your fellow raiders know that hey, that green glowy circle with the pretty flowers floating around it is good, not poison.
That's a complaint I have about these circles of healing (pun intended?). What the hell Blizzard! Making us live solely on the "shit crap on ground, get out or die x_x" mindset, then decide, "hee hee hee healing circles on the ground awesome!"
At least priests and shamans have different color circles. Ours is green. Like poison...
But I digress...
2.) Communicate with your pary/raid.
Raid is normal to have a vast amount of communicating. Doing a heroic dungeon using LFD is a different story. Everyone has that WotLK mindset. Bum rush through a dungeon without CC, strategy, or talking to each other.
No longer are those the days.
Speak up. Don't be that noob who dies to everything because you didn't want to ask. If you have a Boss mod on and are vaguely familiar about what you need to look out for, you'll catch on pretty quickly.
I do find it funny when I do run pug LFD and see the same person die over and over. It's obvious that they are the noob. No one likes looking like a noob.