Most of these issues are just trial and error and you'll figure them out on your way to 70

Tremor Totem is amazing, and if you space them out your almost unfearable.
You need to have the ability to turn all of your characters at the same time, or just turn the main, or just turn the followers. That way if they try to dodge in and out of you, you'll still blast them. (takes lots of time and practice of course)
Shamans also don't come into their own of being very strong until you get the gear to match it, which is usually 60+ when you hit the Outlands.