The Spirit Realm

How about some idea of the content you'll be using the Shaman in? For myself, when it comes to spell damage, I focus on poison and magic damage improvement. Mana preservation for beneficial and detrimental spells is good. You'll probably also want both beneficial and detrimental extension and some kind of a healing improvement focus. Spell haste, I value beneficial spell haste over detrimental spell haste, personally, but always try to have both.

No, thats bad advice. Periodically his shaman will get agro, and because he is running two toons at once, his ability to react the way a main would is limited. Survivability is crucial. Nothing sucks more than fighting down to some location and then losing your healer when you get an unexpected add.