As a shaman, my healing wave (big, slow heal) puts a healing buff on the target that stacks up to 3 times and increases my heals by a good percentage on people.  So what I do whenever I have time is get the buff up by casting rank 1 healing wave (super cheap, and a faster cast) which heals for about 100 but gets the buff stacked so when I do need to drop the full big heal it can crit for 7k and up depending on the situation.  Also, my rank 1 cheap heal can proc the armor buff too when I crit so it's an added bonus when people are topped off and gives me something to do.