Master your positioning
The first skill to master is positioning. "Easy," you may say. "Not quite," says I. The trick to positioning is to be in a central position for ease of totem dropping, being far enough away from the target that any proximity damage ability does not hit you -- and also being close enough that Searing Totem will hit your target. You then need to make sure that you're also far enough from your fellow raiders if there are any targeted AoE abilities as well.
What this means is that if there are no positioning requirements, you'll be 25 or so yards from the target's hitbox. This is both to make sure that any totems you are dropping will affect the melee DPSers (possibly the tank as well) if required, as well as to make sure that your Searing Totem is in range. If there are spacing requirements, these come first and will generally see you just over max spacing distance behind the melee. Do not be afraid to explain this to the other ranged DPS or healers standing near you.
The right totems
Once you have your positioning sorted, you need to make sure that you are using the correct totems. Always pay attention to the other classes in the raid when selecting your totems. This means being familiar with the buff overlaps. The main ones will be Strength of Earth with Horn of Winter from death knights, or Mana Spring with Blessing of Wisdom from paladins.
However, things are never quite as simple as you may think. Always drop your mission-critical totems first. Generally, this means Tremor Totem when there are fears being thrown around, although our soon-to-be-missed Cleansing Totem can be required when there are a lot of poisons or diseases going around. After that, you need to tailor your approach to your group makeup.
Air is pretty simple. Lots of casters? Wrath of Air. Mostly melee? Windfury. Just don't forget that enhancement shaman and frost death knights will provide a better buff than our untalented Windfury (subject to change in the expansion). There's also some debate about whether making sure that your healers have an extra 5% haste is better than your melee being able to hit 16% faster. However, everyone saying that is also an elemental shaman, so we may be a little biased on that front.
For earth, Strength of Earth is the way to go, unless you run into one of the points mentioned previously or you have an enhancement shaman present (also subject to change in Cataclysm). In those cases, it's either Tremor Totem or Stoneskin. Even if there's no requirement for something from earth, it's generally a good idea to drop Stoneskin, because it won't cost you any time and has a negligable mana cost.
Water is a similar situation. If you're going into something with a lot of fire damage (the physical phases of Halion, for example), then Fire Resist is a good choice if there isn't one available otherwise. If that's not the case, go for Mana Spring or Healing Stream, depending on Blessing of Wisdom's availability. Again, if you don't need anything specifically, make sure you have Healing Stream down. At 350 to 400 healing per tick, it can make a difference for your group's survival.
Lastly, fire can be a bit of a contentious choice. You'll want to be dropping Totem of Wrath, either permanently or just every five minutes to get your glyph buff if a demonology warlock is around. You'll also want to drop Searing Totem, so it can come down to a question of whether you want to sacrifice the extra spellpower for your raid (including yourself) for the extra damage from Searing Totem. There's not really any right or wrong answer to that one. There's also Magma to drop (and then use to cast Fire Nova) during AoE phases/trash (although speaking from experience with my alt druid tank, the insistence of everyone to AoE every trash pull right as you pull does not a happy tank make).
Know your moves
The more mobile fights can often leave us eating the dust of other classes, metaphorically speaking. The trick to movement in these situations is to know when you have to move, how far you have to move and being able to do things while you're moving. This means using Thunderstorm, Flame Shock, totem recasts or even Frost Shock while moving, depending on the situation.
Yes, I did say Frost Shock there. FROST SHOCK! Ahem. Seriously though, Frost Shock can be useful when you're on the move, especially if you've just recast Flame Shock. The reason for this is that even though Flame Shock has a higher overall damage, most of that comes from the DoT, so if you're overwriting the DoT straight after casting it, you "lose" a lot of potential damage.
Similarly, recasting totems while moving is always a good idea. I try to cast mine a few seconds before I stop running, so that I've got them fairly close to ensure good raid coverage. This is doubly important for Searing Totem. On the other hand, Thunderstorm will be useful for keeping your mana topped up (although be careful about using it near mobs that aren't knockback-immune if you aren't glyphed, else your tanks may not like you that much).
The use of cooldowns is always an interesting topic. Some of you may recall the discussion, blog post and eventual article around execute effects and how they interact with cooldown use over at Elitist Jerks early last year. One of the things I've learned over the years is that while stacking haste effects may make you cast really fast, it makes no difference if you use each one individually -- and this can even be preferable, depending how close to the one-second global cooldown you are.
In fact, you can apply that to other temporary buff effects, too. Combining buffs of different types, be it spellpower, crit, haste or damage buff, will be the same, if not better, than combining two buffs of the same type.
Show your totemic mastery by reading Totem Talk. Whether it's Matt Sampson's elemental edition, Joe Perez's coverage of restoration or Rich Maloy's enhancement edition, we have you covered.