It helps me to keep my shields up more often.
#showtooltip
/cast Shimmer
/cast [spec:1] Arcane Barrier
/cast [spec:2] Blazing Barrier
/cast [spec:3] Ice Barrier
EDIT: Just came up with an additional macro to help keep the Barriers up:
#showtooltip
/cast [spec:1] Arcane Barrier
/cast [spec:2] Blazing Barrier
/cast [spec:3] Ice Barrier
/cast [flyable] Squawks ;Sinrunner Blanchy
Obviously you would replace: Squawks with your flying mount and Blanchy with your ground mount. Also to note, you must put the Mounts part of the macro after the Barriers part or the Barriers wont cast for some reason. I am no macro pro but I try to learn as I go.