This is the 1 button tanking macro I've been using (found on this forum)

As the other poster said - make sure you have Righteous fury up, and a seal of your choice.

/castsequence reset=combat Holy Shield, Hammer of the Righteous,
Judgement of Light,,Consecration, Hammer of the Righteous, Holy
Shield,,Judgement of Light, Hammer of the Righteous, Consecration,

once you get shield of righteousness add it between the 2 commas and at the end

It's worked like a treat. Basically shield pull and start tapping your tanking macro. I found in manatombs it was best for me to wait till consecration hit before starting to DPS on my shaman.

If i didn't I found the spell casters stood off and hit my shaman.

Make sure lay on hands is handy - I only ever plan to use it for the tank, but my 71 resto shammy just keeps him alive, so he doesn't have to use it.