Shaman is one of 3 healing specs that can do its full healing while not having a target to attack, so your group may be relying on you to do big healing when you have to run away from the boss.
Your group will appreciate wind rush totem.
During the phase where you destroy the spikes, Earth Elemental can help tank the assasins as soon as they come out of stealth.
Spirit Link Totem can be great to stabilise the health of the group early into the obsidian statue phase. Try to prioritise chain healing off of dps who have burst cds up and do not have personals up. Earthen Wall Totem is great for this phase as you will get its full absorb amount, between Spirit Link, Healing Tide and Earthen Wall totem you can really carry a good portion of the phase with your cooldowns alone.
The Prophet Skitra
Dark Inquisitor Xanesh
If your raid chooses to let the Drones explode then a quick Spirit Link Totem as it explodes can help you survive the damage and also heal up the damage with Spouting Spirits. Keep an eye on the boss's energy, every time it reaches 100 the bosses will change control and thus trigger the raid-wide damage.
Shad'har the Insatiable
Keep an eye on who is getting stunned by Mutterings of Insanity and make sure you prioritise dispelling any other healer who is targeted. You can place Spirit Link Totem into the Tentacles to emergency heal players who are blocked from your line of sight by Void Miasma.
Take advantage of being the only healer with an interrupt, use Wind Shear often on the Mindflay casts. Be prepared to single target heal tanks often, they will often be away from the rest of the group so you will want to riptide / healing wave / healing surge often instead of casting chain heal on them.
Ra-den the Despoiled
Make sure not to chain heal on players with the Corrupted Existence debuff in last phase unless they are very low.
Focus on making sure everyone is above 50% health before new Corrupted Existence debuffs are applied, as otherwise they can 1 shot.
Carapace of N'Zoth
N'Zoth the Corruptor
If basher tentacles are dying slow, use Earth Elemental to tank new spawning ones so your melee don’t get killed.
If playing with Holy Paladins, focus your chain healing during Evoke Anguish on the ranged players that will be out of range for them.
If your raid group lacks immunities you can soak a Thought Harvester and then die before you get mind controlled, and Ankh or Ancestral Protection Totem.
The Eternal Palace
Abyssal Commander Sivara
Radiance of Azshara
Earthen Wall Totem and Healing Rain are great for the constant low damage of arcane missiles. You can also opt for Ankh totem for last phase to suicide players who are about to die from the Essence of Azeroth buff from using the console, enabling you to save a battle resurrection. Well timed cloudburst totems are really strong for the Charged spears in Phase 3.
Crucible of Storms
The Restless Cabal
Healing wise, shaman is not so great for the fight due to being spread a lot of the time, you will not pump high numbers but just play smart and spot heal those that need it before the boss' 100 energy casts.
Due to the scripted nature of the fight, you should always be able to get big cloudbursts off after the boss's 100 Energy casts (except in phase 3 where you cannot heal allies).
Battle of Dazar'alor
Champion of the Light
Grong, the Jungle Lord
Big jump up from the 1st boss in terms of healing.
If your raid is positioned well you can get both the melee camp and ranged camp in your healing rain / spirit links. This fight has a lot of potential for doing good Cloudburst totem and High Tide combos. Your raid raid leader or healing officer should assign cooldowns for each Tantrum.
This fight has an important dispel mechanic: Searing Embers. The raid will get debuffed with varying length magic effects. When they expire without being dispelled, they do raid-wide damage. You can survive missing one of these, but more than 1 is deadly. You and all other healers should be reacting to this ability fast and dispelling the players with the debuff.
Healing wise there are only a couple of dangerous parts to this fight.
The 2nd time the raid could be in danger is during the maze phase when the boss casts A Flash of Hostility. Your warlocks can place gateways that take you from the start to the end. SpiritWalker's Grace is great during this phase, and if your raid is struggling to survive you can pop a healing tide totem while running also.
As a healer there are 2 gems you can take. Healing rain and cloudburst totem are your best ways of applying the gems, but you should be sure to spot heal with riptide the people that are standing outside of the melee stack.
If you are the healer that picked up the Amethyst of the Shadow King, it is important that you ensure everyone has the shadow-touched debuff applied to them when their Thief's Bane debuff runs out to prevent a 1 shot. It is also important to have it applied to the raid before the boss does Wail of Greed, It can be good to Healing Tide Totem 1 second before the Wail of Greed to ensure the raid has the damage reduction applied.
In the last phase the biggest tip I can give you is to ensure the people running out of the raid with Liquid gold receive a lot of healing, especially if Wail of Greed is coming soon Riptide and healing surge spot healing on these people are important.
Conclave of the Chosen
This is one of the fights were Earthen Wall Totem can get good value as the Paku’s Wrath phases are exactly 1 minute apart. However as always Ancestral Protection Totem could save someone if you spot them getting knocked out of the safe zone by the leap (Krag'wa's Wrath).
Your raid leader or Healing Officer should assign raid cooldowns for each Paku’s Wrath.
Good Capacitor totems can stun the Ravenous Stalkers that are fixating people, try stunning them when they are close to the boss to help them get killed faster.
As a Shaman you can dispel curses which means you should be constantly watching out for who may need Bwonsamdi’s Wrath dispelled. Players that need to be dispelled are: Players on dangerously low health, players that are not full health during or before a Paku’s Wrath, players with the Bleeding Wounds debuff, and tanks.
You should also dispel players with Mind Wipe as quickly as possible.
Wind Rush totem is great for this fight, especially if you go into the inside phase, during Bwonsamdi’s Inevitable End, you can help your group run away from him faster and not get dragged through any Death’s Doors.
Another fight where you could consider Earthen Wall Totem, simply to use for the 1 tank standing outside with Bwonsamdi. The tank’s are usually the only people in danger on this fight so pumping lots of healing waves and keeping Riptides on them is a priority.
Make sure your tank is standing max melee range and that you are standing right on the edge of the circle, that way you should just be in range to heal them without gaining stacks.
Tremor Totem is particularly powerful on this fight, you can negate the effects of the Zombie Dust totem which will save your group a lot of trouble. You need 2 shamans to cover every Zombie Dust Totem.
High Tinker Mekkatorque
During Wormhole Generator 2 players will get knocked up and 2 players get polymorphed. This is the most crucial part of the fight for healers. If you are not a goblin, you will need to call for a leap of faith if you are knocked up.
You need to ensure that if you are knocked up you call for a leap of faith to quickly get back to the ground and get away safely. If not, you need to prioritise dispelling the discombobulation players so that they can also escape to safety.
During each Crash Down you will be tempted to chain heal for maximum HPS, and that is fine, as long as you first ensure that everyone will survive the damage, if there are players lower than 70%, prioritise single target healing them up in those precious seconds with a riptide, rather than pumping the chain heals. Each crash down is also a great place to explode a cloudburst totem.
Your raid leader or Heal officer should assign cooldowns to each crash down, with extra assigned to the ones that overlap with the Wormhole Generator.
This is a great fight for Resto shamans, you can run either Ancestral Protection Totem or Earthen Wall Totem here. As the raid is so stacked you can do a lot of healing with chain heal and healing rain, and pop big cloudburst totems when needed.
You can save lives by using Spirit Link Totem or Ancestral Protection Totem whenever the group is standing in lightning orbs or if a player is being charmed by a siren and dragged through an impending sea swell.
If running Igneous Potential traits on this boss, you can do a lot of damage, especially to priority targets such as the Sirens. When you see the sirens are coming soon save 2 charges of Lava Burst and have your flame shock cooldown ready. You can easily match the top DPS on their damage done to sirens.
Lady Jaina Proudmoore
Ancestral Protection Totem and Earthen Wall Totem are both great for this fight. If your raid opts for the strategy of sacrificing the tanks in last phase like we did, then Ancestral Protection Totem is the way to go. You get the additional benefit of saving phase 1 wipes during scary Avalanches as it will be back up ready for the last phase. If you do not require the Ancestral Protection Totem, Earthen Wall Totem will provide a large amount of healing throughout the fight, and can help soften the damage during high chilling touch moments.
Wind Rush Totem is great for helping your raid in the 1st intermission, and for helping your raid run up to Nathanos faster during the 2nd intermission.
You can go into Ghost wolf in the few seconds the boss is doing role play before the 1st intermission starts, this way you will have full Spirit Wolf stacks as soon as the intermission starts, as it continues to build during the cut-scene.
You should aim to leave phase 1 with almost full mana. The first phase healing is very low.
Spirit Link totem with spouting spirits will keep your raid healthy and stabilized during the last phase and when you leave the 1st intermission.
Your raid leader or healing officer should assign all cooldowns for the last phase of the fight, having good CD assignment in the last phase will make a massive difference. Other key times in the fights for healing CDs are the last siegebreaker of phase 2, and when you leave the 1st intermission.
Dispel those who get Grasp of Frost quickly, you can see who will get rooted just before they get rooted by their Chilling Touch debuff increasing shortly before. This is because the root has a travel time but the Chilling Touch is increased instantly.