Ifrit is a pretty good go to practice w/o being stressed. You have to place / replace your fairy after knockbacks . Got to position yourself well and can weave in aeatherskills and pre-shield ifrits skills. All that without screwing the group if you fail sth course the other healer should be able to soloheal it.

Or empty your skillbar and insert skills for every 5/10 Levels and run dungeons of that lvl. Not as good as leveling up but you´ll get a feeling what thos skills can do and what not. Often dungeons are built for those skills you get 1-2 after being able to enter. Chances are you have to suffer first time. Get the skill and say "boh easy".