Like all other classes, Shaman abilities are broken down into 3 spheres: Restoration, Elemental Combat and Enhancement. The Restoration sphere centers around healing and cleansing. The Elemental Combat sphere centers around casting abilities. The Enhancement sphere centers around melee abilities and buffs. These spheres are important, but what really sets the Shaman apart from other classes are the use of totems. Each previously mention sphere contains totemic abilities related to itself but the totems are really broken down by the element used to case them.
A Shaman can lay down one totem for each element they have mastered: Earth, Fire, Water and Wind. The elements are mastered via quests that the shaman must complete. Earth is received after a level 4 quest, Fire after a level 10 quest, water after a level 20 quest and Wind after a level 30 quest. When these quests are completed, the Shaman will receive a totem of that element. That totem must be present in the bags of the Shaman if they wish to put down totems that use that element. In other words, when you receive the Earth Totem, the Earth Totem must be in your bags if you want to cast a Stoneclaw Totem. So do not leave them in the bank or destroy them.
See also 
Note that Rank 1 of all spells and totems is listed below.
|The first available totem, this totem will protect the shaman and party members from melee attacks. It won't fully block them but will reduce the incoming damage. Lasts 2 minutes.
|This totem can be useful for mobs that run when low on health, it slows the movement speed of mobs within 10 yards of the totem. Lasts 45 seconds.
|Taunts enemies within 8 yards causing them to attack the totem. Mobs attacking the totem have a chance to be stunned for 3 seconds. This totem has more health than other shaman totems so that it can withstand the attacks for a little longer. Note that the taunt isn't a very heavy duty one so if you've attacked the mob first and then put down the totem, chances are the mobs is still going to attack you. It's useful when you pull adds (intentionally or not). Lasts 15 seconds. This will not work in PvP on players but it can briefly distract pets/minions.
|Strength of Earth Totem
|Increases the strength of party members within 20 yards. Lasts 2 minutes.
|Removes Fear, Charm and Sleep effects from players within 20 yards. This isn't a straight protection from or removal of those effects, however. The totem sends out pulses and the pulse is what removes the effects. It is possible for a player to get feared out of range of the totem before the pulse removes the effect so it's not completely reliable.
|Earth Elemental Totem
|Summons an earth elemental to protect the shaman and party members for 2 minutes or until killed. Note that the elemental is uncontrolled. It's got a fair amount of health but doesn't do a great deal of damage.
|This totem will attack enemies within 20 yards with fireballs. It's a little like have a really stupid imp around. Note that you cannot control which target the totem will attack if several are close to it. Also, while this totem can lend some nice extra damage, you'll want to be careful when you place it as it will sometimes pull additional nearby mobs when you're not ready for it to do so. Lasts 30 seconds.
|Fire Nova Totem
|This totem lasts 5 seconds, if it is not destroyed within 4 seconds it explodes and damages all enemies within 10 yards with fire damage.
|Frost Resistance Totem
|Provides additional frost resistance to all party members within 20 yards for 2 minutes. Note that this does NOT stack with paladin resistance auras.
|Totem pulses steaming hot magma at all enemies within 8 yards every 2 seconds causing fire damage. Lasts 20 seconds.
|Enchants the main hand weapons of all party members with a weaker version of the shaman's personal Flametongue Weapon enchant. Note that it will not overwrite the shaman's own weapon enchant. In other words, you can't have the effects of 2 enchants on your weapon (the one you applied and the one from the totem). Lasts 2 minutes.
|Totem of Wrath
|Increases all party members' (within 20 yards) chance to hit and critically hit with spells.
|Fire Elemental Totem
|Summons a fire elemental for 2 minutes. This elemental has less health but causes far more damage than the earth elemental totem.
|Healing Stream Totem
|Heals nearby party members for a small amount every 2 seconds. This totem won't obviate the need for a healer around but it can help to slowly top people off who are taking incedental damage. Lasts 2 minutes.
|Poison Cleansing Totem
|Removes 1 poison effect from nearby party members every 5 seconds. A situational totem, but it can be very handy during encounters where multiple party members are repeatedly getting poisons applied to them. The cost of the totem can save you mana on cleanses (a single cleanse costs 7% of your mana, a 2 minute totem to cleanse all party members evry 5 seconds costs 8%.) You just need to balance whether the mana savings on clases are worth not having a different water totem down. Lasts 2 minutes.
|Mana Spring Totem
|Restores a small amount of mana every 2 seconds to all nearby party members. Like Healing Stream, it's not likely to remove the need for MP5 gear but it can be nice to have to help a party replenish mana in between fights and can give a little boost to existing MP5 during long ones. Lasts 2 minutes.
|Fire Resistance Totem
|Increases the fire resistance of all nearby party members by 30. Lasts 2 minutes. Note that this does NOT stack with paladin resistance auras.
|Disease Cleansing Totem
|Removes 1 disease effect from all nearby party members every 5 seconds. Like the poison cleansing totem, this one is obviously situational, but in encounters where party members are getting, well, diesased it may be worth the cost of the totem.
|Mana Tide Totem
|This totem can only be achieved through talents in the Restoration tree. It summons a totem that returns 6% of total mana to all party members every 3 seconds. Lasts 12 seconds. This is much more useful as a mana return than the mana spring totem. Additionally, not only will it help the healing shaman as well as any caster DPS, it can also help paladin tanks not become mana starved during long encounters. (paladin tanks love Shaman healers for many reasons, this is one of them)
|Nature Resistance Totem
|Increases all nearby party members' nature resistance by 30. Lasts 2 minutes. Note that this does NOT stack with the hunter nature resistance aura.
|Redirects one harmful spell cast on a nearby party member to the totem (the totem is destroyed in the process). This totem can make certain encounters nearly trivial. The Maiden fight in Karazhan is one of these - a shaman keeping the grounding totem up will completely eat all of Maiden's Holy Fires (a DoT spell that can easily kill players with low stamina if it isn't cleansed quickly enough).
|Enchants the main hand weapons of all nearby party members with wind giving them a 20% chance to gain an additional attack that also gets a boost to attack power. This functions much like the shamans own Windfury Weapon. If your group is heavy with melee DPS, this is the totem to use. Warrior tanks quite like it as well.
|This totem has slightly higher health than other totems and will warn when enemies attack it. Additionally the Shaman can view the area "through the totem's eyes" so to speak, giving the shaman the ability to see what's going on around the totem. This can be very usefulk in PvP situations to be aware when people are approaching a specific/strategic area.
|Much like the stoneskin totem reduces damage from melee attacks, the windwall totem will reduce incoming damage from ranged attacks.
|Grace of Air totem
|Grants all nearby party members a boost to their agility. Lasts 2 minutes.
|Tranquil Air Totem
|Reduces threat generated by all nearby party members by 20%. Lasts 2 minutes. This totem can be very helpful in a group with a lot of ranged/caster DPS, however you really want to use caution on its placement. If you place it too close to the mobs (or the tank has to reposition the mobs into its radius) then you're severly gimping your tanks ability to, well, tank. Make sure this is well away from where the mob is being fought and near the ranged DPS.
|Wrath of Air Totem
|Nearby party members have their spell damage and healing boosted by 101. This is another totem that paladin tanks love as most of their threat comes from holy spell damage. Additionally, if your group is caster DPS heavy, then this is a great totem to use.