What do you do to stack your group/raid's deck? I guess this could mean classes, but really I'm wondering what you do when you put the groups together.
Me, I don't start invites until I have the tanks and heals covered, minimum. There's no point in getting people's hopes up without those key roles, and the impatience factor can seriously hurt anything happening without them!
For tens, I keep tanks and heals in the same group if there is a healing priest present. If there's no priest, but there is a healing shaman, and I build the tank/shaman group around those that will be in range of the totem. Onyxia this is pretty classic. Tanks, melee and shaman is told to always be in range of that tank with their totems.
On to the dps. DPS is so hit dependent, I build my groups around Heroic Presence. It is so good to be playing in the Alliance faction with that handy little feature! After duking it out with a past raid-leading-team that tried to put my draenai healer into a group that made little sense with her totem applications, whenever possible I put melee draenai with melee dps, and ranged draenai with ranged dps. This is because totems and heroic presence are range dependent. Sticking like ranged toons together, based on the necessities of the fight, is the optimal way to group them up.
I've been lucky that in my 25man raiding career we usually had a plethora of shamans. 2 enhancement and 2 resto, most nights. This means we had 2 resto split between the healer group and caster group (yay mana tide totem usage, not to mention the other buffs being shared) and the enhancements were put into the tank group1 and a melee group. This left a tad bit of quibble room on the last group, but the benefits for the rest with added healing, hit coverage, fear protection, extra dps, all seemed worth it.
It doesn't always work out that way tho. Sometimes groups have to be built on their assignments. Onyxia is another great example because half the raid at least is focusing on running about and killing the big dragon, while others are killing adds. Grouping those teams together where possible makes good usage, too! Let's face it, it's not on every fight that we can all be grouped up together and hope everyone gets coverage with everything. Group-limited effects really spoil that, too.
What I've never really wrapped my mind around before is raids that have both sanctuary and kings up... /boggle
What do you do to build groups/raids? What did I forget?