Advice from a 31 conjurer who didn't bother using these spells forever: (cue song "I Wish that I knew what I know now...")
Make frequent use of Profundity and Spiritbind.
Profundity can take a regular spirit bolt and make it hit for 3-4 times its regular damage, often tripling or quadrupling it's SP gain. Yes it costs a good chunk of stamina. Pop it off at the start of a battle.
Spiritbind is really much better than I thought at first. Nuke spells are a great way to get good SP (I've gotten 200+ SP from nuking in larger parties), and this is an ideal way to do so more efficiently. This is NOT useful for solo'ing or in "scorched earth" parties where you just run around killing easy mobs for 40-70 SP at a time. It is ideal for drawn out battles where you will be doling out damage and healing and hoping / expecting 400-500 SP.
Spiritbind words for those situations where you're going to be spamming your heals as well. Do us all a favor and spam Cure I when you spam (unless Cure II absolutely necessary!).