For focus macro:

1. /assist Main_Char_Name - allows you to choose who's gonna be main char aka focus target

2. /focus target - now Main_Char is you focus.

3. I like this macro for healing Main_Char's target:
/target focus
/assist focus
/cast Heal
/targetlasttarget

(you can remove /target focus I think, dont remember for sure)

4. For selfheal I have separate macro for each shaman:
/target Shaman_Name
/cast Heal
/targetlasttarget

5. Also good macro for all healing classes in the group:
/target focus
/cast Heal
/targetlasttarget