instances and you.

As I have been gearing up my enhancement shaman there comes a tipping point where no one wants you, to everyone wants you.
Its a combination of gear/gems/enchants, reliability when running instances, availability, and really knowing your character.

You can find info on gear and the like at EJ.

And reliability just comes from staying until the end of runs. If you are always making yourself available, with consumables, (if need be) and staying until the end, people will add you to their list and when they run stuff will look you up first.

I know that people don't like replacing folks in their group, especially since they have to run out and summon, after they find someone that wants to run a partial instance.

The other thing that comes with that, is knowing how much time you have and knowing how long it takes to do a particular instance. Heroic Occulus comes to mind.

Some of this might sound really obvious but it bears repeating because no one really talks about it.
How often does someone say to you, "thanks for being available, not bring your personal problems to the group, and staying until the end even though you lost all the rolls" ;)

The last thing is for me in particular as a shaman.
We have a wide range of totems and spells and abilities that make us useful in a lot of different fights, its one of the biggest things that I like about being a shaman.

And it all comes down to knowing fights and knowing mobs and trying different things.

Let me give a few examples:
Whenever I see a mob with an ability I the buff area of the unit UI, I find out if I can purge it. If he then starts casting something like a healing spell, Earth Shock it to see if I interrupt it. If its a harmful spell, I through down Grounding totem. If shaman friend doesn't say that it has been absorbed by the grounding totem, then I know not to through it next time.
If the boss is tossing around diseases, fire attacks, frost attacks, poisons and the like and the healer is having a tough time keeping everyone up to 80-100% I through down totems that negate that damage, and that means that everyone can fight longer because the healer isn't out of mana.

Now you might say that you should just DPS them down
If everyone is taking the full amount of damage, then the healer is going to be doing lots of group benefitting heals.
When something crazy happens, the healer might be out of mana from mana inefficient group heals and have no breathing room to bring everyone back up
Or he/she might be focused on the group and not the tank for a second, and he might be close to death.
By giving them the healer breathing room, we can go the distance in the fight.
And as a dps class that has healing spells, when the healer is working on the tank, I might toss a instance chain heal or put the healing totem down for awhile.

Now, that takes a hit in dps meters, but I am ok with that. Even as a great DPSer its nice to take a hit in the meters and say, my benefit is intangible as long as everyone else sees you as a contribution.

A tank's contribution is to tank, as long as no one dies, he is doing his "job"
A healers contribution is to heal, as long as people mostly don't die, he is doing his job.
Pure DPS classes contribution is to go all out on the mobs and kill them as fast as possible. And someone invented dps meters to show the contribution each dpser adds.

Everyone can see the value each brings, but shamans are unique in that they can DPS and heal without changing forms, we bring more than "just" dps. We bring totems, and more fight management tools.

A person that rolls a rogue or dps warrior, that then rolls a shaman is going to try to play it that way, maximizing Attack power and Crit and I don't think that's the intent of shamans, even though everyone wants to pidgin hole us into that role.