You will probably get this while trying to obtain master summon/command/magic and kill the "weapon" super bosses. Farming "magic pots" not only gets you 1000 ap each, but also 8000 Xp each so you can reach max level in just a few hours. You can get exp boost materia in the golden saucer in wonder square for 2000 GP, you can get GP easily from chocobo racing. Exp boost can get you 1.5 times exp at level 1 and 2 times exp at level 2 (no change at level 3), and The boost only applies to the character equipped with the exp boost materia not the whole party.
Just farm magic pots using the W-item glitch to dupe elixirs and level up as you master your materia. Use this video for more info on farming ap and at the same time you'll be leveling relatively fast. Two birds one stone.