Here is generally my way of doing things. I'll go as indepth as I can.
This is gonna cover more than just regular healing.
----Pre Battle----
1.) Lay WoA totem, cast Earthshield on the tank.
2.) Lay my usual assortment of Totems, Mana Spring, GoA/WoA, SoE/Earthbind BEFORE the tank aggros. If you are unable to set your totems before the battle, then set 1 in between each large Healing Wave.
3.) Before the tank initiates cast Water shield on myself, and cast a rank 1 Healing Wave on the tank 3 times to stack healing way buff, and hopefully get a lucky crit in for Ancestral Healing.
4.) I usually pop my trinkets here depending on the fight. Beginning is always a good time, as it is the hardest phase for a shaman.
----Battle Starts----
4.) A split second before the tank hits, cast Gift of the Naaru on him. With enough +healing this HoT spell can help quite a bit, especially if you are forced to change targets from the tank to another member. Mine heals for around 3200-3500 depending on how many buffs i have on myself.
5.) Make sure I still have water Shield on myself.
----Tips----
Healers have a hard time in Raids/Pug Groups due to getting blamed for most things. A lot of people do not realize that the tank has a lot to do with your heals also. You have to have a tank that can survive at least 5 hits from a single target. More is obviously better. And you CAN dwindle that number down to 4, depending on how geared your are. But any lower and you can be in big trouble if the tank gets critically hit once or more.
Shamans have the disadvantage of no reliable HoT, so all of our heals are direct meaning we can only do a set amount ever 3/2.5 seconds. If your tank cannot survive 5 hits, you are going to have a very very hard time during that party.
----Battle Again----
6.) Chain Heal/Lesser Healing Wave is what you will use on the party. Chain heal is very mana efficient as long as it hits 2+ allies. If it doesn't , then do not cast it at all. Unless you are very confident that your tank can survive a few hits unhealed, then do not be afraid to cast Healing Wave on an ally, if not Lesser Healing Wave is the only way to go, save for Chain Heal (But again only if it can hit multiple targets). If your tank is getting beat on you most likely do not have the time to cast a 2.5 second heal on a single target.
7.) Make sure i still have water shield on myself.
----Chain Heal (Tank)----
This is what most people do with Chain Heal. Use the Tank as the center, and let it fly. Very useful on pets, and to some extent your allies. Although in reality your teammates should be no where near the tank unless they are melee. If they are near the tank and they are ranged, make sure to tell them to back up. Warlocks/Mages/Shadoe priests have very large threat generation. The further back they are from the mobs, the longer the transition time if the Mob switches targets from the tank to one of your Range Allies. This lets you place a Earthbind totem to help them as quickly as possible.
----Earthbind Totem----
No matter what anyone says, this totem is your #1 friend. Wrath of Air is nice, Searing totem is just plain cool. But nothing does as much for you as this one totem. I suggest you put it in an easy access spot on your menus (Or better yet, hotkey it). While Earth Elemental replaces this totem to some extent as your O @$%^ button, nothing can ever replace a totem that does so much for the party.
If you ever find yourself pulling aggro, first thing you do is set an earthbind totem. Back up about 5-10 Yards depending on how close the mob is to you. Wait for earthbind to take effect, and RIGHT before the mob hits you, rush forward.
Now you might be thinking "what an idiot, don't go towards the mob" but this is the BEST course of action. Why? If you go to far back the mob will go out of the range of earthbind for one. For two, your tank is probably on the OTHER side of that mob, and in a dire situation you always want to run to the tank so he can get the aggro off of you quicker. If your thinking "He will just hit me twice and I am dead". This could be true actually, but on most mobs that can 1 hit you, if your tank loses aggro your entire party is gonna wipe anyways.
Shamans have a great advantage over clothies/Leather, in that we can survive a couple hits. The mob will most likely hit you once, but that Mob WILL have to turn around. That combined with the earthbind will give you enough time to take 1 hit and then get out of melee range before he can hit you again.
Any good Shaman will tell you that this strategy WILL save your life (Alot).
(Just please remember that some Mobs are resistant to Earthbind, so knowledge of the mob really helps.)
----Frost Shock----
You can use frost shock to some extent the same as Earthbind, although I definitely prefer Earthbind. This tactic is called Kite the target. Basically you just keep yourself out of range, and just keep him slowed enough so he cannot get to you.
The problem with this is you have to be facing that mob, and there is only one direction you can go, backwards. If you turn around, you will not be able to cast frost shock anymore because he is not in sight. So after 6 seconds he will be right back on you.
This should only be used in desperation. Always use Earthbind before this, as it is more reliable.
----Battle Continued----
8.) Recheck totems, Totemic Call + Replace the ones if they are about to expire.
----Totemic Call----
Do not EVER let your totems just die out in a fight. Always call them back with Totemic Call right before they expire. This will maximize your Totems, thus increasing your Mana Efficiency.
Mods can help with this a lot.
----Battle----
9.) Make sure I still have water Shield on myself.
10) Look at my Mana, if I fall below 40%, immediately cast Mana Tide Totem (Unless of course you can tell the battle is about to end, then that would be pointless)
----Boss Battles (Heroism)----
Heroism is something I see many Shamans having trouble with. "When should I cast it?" "What if I cast it to soon". In most boss fights there are no "Set" times to cast Heroism, most not all. Bosses such as Shade of Aran in Karazhan do have things you can base Heroism off of, Water Elementals. Others, Prince for Example, has a period of time where he does massive damage, AKA Phase 2. You want to DPS him as quickly as possible during this phase, so casting Heroism is a good idea.
If your boss fight has no real set time, such as the above battles. I usually cast heroism it around 40%.
MAKE SURE YOU WATCH THE THREAT METER WHEN YOU CAST HEROISM. I have seen many a Shaman just throw out Heroism thinking "O hey a nice DPs boost now would be great", not even thinking about their party members and their threat. A 30% increase in Casting speed is A LOT, and will most likely send your top DPSers off of the charts (AKA pull the aggro of your tank thuse wiping your party)
----Ending----
Eh, I wrote this up pretty quickly. So if you have any questions, or if someone sees I left something out, sorry :(.