FFXIAH.com

It's all random on how long it will take for you to learn a new spell. I've learned some on first kills to about 20+ kills. The longest one for me to learn was at about 33 kills and it was a spell that wasn't important at all to me. I just wanted it to feel complete. Ironically, the other powerful popular spells I got within less time vs the not so popular ones.

My suggestion is when youi're around Lv40, mobs get a lot tougher to solo for spells. With a little patience, ask a friend to help you kill them.