Hey there, Smed!
Uglutz has hit the nail on the head (especially since Ive learned much of how to heal from him ;p). If I could make another suggestion: go to the link I'm posting below and get the macro for casting a nature's swiftness using tidal force. It will allow you to choose a chain heal or greater heal and quickly throw one out in those oh crap moments. Also, make sure you have earthliving weapon up. Lately, Ive been doing a little more healing, and I find that if you have a well-geared tank, you can keep the main tank up in non-boss fights with ES, riptide, and earthliving alone.
Should you choose to foray into enhancement, just let me know, and Ill show you how to steal aggro like a champ! ;p
Here is the post I promised: EJ Resto Shaman Thinktank
There is also good info there on gem choices that you could use.
Let me know if I can do anything else to help.