How can you heal effectively in WoW Cataclysm heroics

The answer to this question depends largely on your class and talents. On a general note, the healing mechanics have changed so that you have to be more careful of who you heal, and can't spam your heals.

The basic strategy below should get you through most encounters - but nothing beats practice to get the hang of it. The specific class-based descriptions at the bottom are variable, as healing styles may differ between healers - so take them as advice, not gospel, and experiment with them. In all cases, don't be afraid to ask advice from a more experienced healer in your class.

General Strategy

The basic strategy is that the tank needs to be as close to full health as possible, and that the DPS can hover around 40-50% health without it being a threat unless they stand in fires or ignore the mechanics of an encounter.

It is also much more important to interrupt boss effects (such as Shock Blast on Lady Nazhjar or the various heals) or to dispel from party members what you can. This in effect is more effective healing mana-wise than simply healing them up without removing the debuff.

It is critical to know what a boss will do, and react to it. If the boss is right before a big AoE, using HoTs for some healing before the blow (or Aegis for Disc priests) will make it easier to get everyone up.

The most important change has been to mana, and using your mana cooldowns wisely, because Blizzard has changed the game to discourage spamming heals.

Every healing class has one or more ways to regain mana or to make their heals cheaper, which should be used to keep your mana as high as possible. For example, a Druid regains mana from Lifebloom, so it is in your best interest to keep it rolling on the tanks. A priest can use Shadowfiend to regain a big chunk of mana, and it should be used at about 50% mana to make the most use of it.

Specific Classes

The manner in which you do this depends a lot on your class. Paladin healers combine Beacon of Light and Holy Light to heal efficiently, using Guardian of Ancient Kings and Lay on Hands as cooldowns. Paladins regain mana by getting a critical effect on some heals, making their primary stats Intellect, Crit and Haste. High Intellect also gives some Crit, making that stat doubly important.

Discipline Priests use Penance, Prayer of Mending and a macro combining Inner Focus with their Greater Heal. Smiting deals damage but also heals the melee, while stacking up Evangelism to make Penance cheaper. They also generate a "shield bubble" on people through Divine Aegis by getting a critical heal or casting Prayer of Healing. They use Divine Hymn and Binding Heal in emergencies. Power Word: Shield is used less for shielding the group, but rather for the Haste bonus it gives, making their next heal quicker.

Restoration Druids roll Lifebloom on the tank, which triggers replenishment, returns mana to them occasionally, and is a base trickle heal on the tank. Rejuvenation and Regrowth are used for preparing a group for large AoE damage, and Swiftmend can be used effectively to bring someone to tolerable health levels afterwards. Healing Touch is the base heal for Druids, which is not the fastest heal but efficient. Wild Growth, while still a nice HoT layer, is less efficient now. In emergencies, or when almost out of mana, you can use Tree of Life and rolling lifebloom on the group for massive healing and mana returns.

My knowledge on Holy Priests and Shamans is insufficient to give more information, except that Holy Priests rely on Heal and Renew, empowering themselves through Chakra. Shamans use Earth Shield and Healing Wave as base heals while using Chain Heal for emergencies.