I'm leveling my Pally/Shammy team right now, so I can identify with your pain. I'm currently 71 so I have some tricks you might not.

Like others said, always keep water shield up. It's free, so just hit it on all shammies when it gets low on one.

For normal mobs, I just hit them with a lighting bolt, or chain lightning if there are mobs it can jump to, followed by an earth shock. Usually the first lightning bolt will kill them, but if not the earth shock finishes them off. Mobs beyond the first one get lightning bolts and shocks as needed. No totems.

For elites I usually just drop all my totems. I have my numpad set up for totem binds and it's easier to just drop all 16 than try and micromanage them. Lightning bolt and shocks till it dies. I drop four fire novas if there are enough mobs to make it worthwhile and occasionally thunderstorm to get them back some.

PvP is very situational. So far it's pretty much just consisted of multiple 80s falling from the sky and making me into fertilizer, but if I have a chance to I drop grounding and tremor totems followed by fire nova for the stun.

The thing you are likely adjusting to is the caster versus melee switch. Up until a few days ago I was leveling an all DK team. Switching to shammies was a jolt to the system and it feels slow. For questing the healing just doesn't seem to matter that much. Every mob dies in about the same amount of time, but the shammies have a cast time associated with their two attacks where the DKs just had to deal with GCDs. I think the other thing that gets to me is the need to stand still. With melee you are cosntantly moving so things feel like you are always doing something. Casters have to stop and stand still everytime you need to deal with a mob. It's the stopping all the time that makes it feel slow.

- Souca -