ES + Glyphed LHW for tank healing. Chain heal(preferably glyphed but not required for 5-mans) for group healing. Refresh water shield frequently. You don't need to pay attention to the charges, just refresh it frequently, it costs no mana. If you have good mana regen you can simply use ES and CH spam on the tank which will get you through almost anything, but when you're starting out you probably don't have that regen. Get the minor glyph that adds an extra orb to water shield, can't recall the name. Set up a riptide the tank button for when you need faster healing, and a NS+TF+HW macro for an emergency. Sometimes I'll riptide the tank before a pull but it isn't necessary 99% of the time.

Basically your buttons should be:
ES the tank
WS
LHW the tank
RT the tank
CH the tank
CH self(or if you have the means to target specific party members do that)
NS+TF+HW emergency
All the other generic shaman stuff that you want like BL, totems, and other such perks.
Earthliving weapon, but since it's only once every half-hour you can do it manually instead of taking up a button.

At minimum, you need to keep your shields up, have a tank heal, and have a group heal.