Final Fantasy X Tips

100's of AP
When you fight Sin on the boat for the first time , simply forget the fin and pound the sinspawn that keep on coming. With Cheer on 4 or 5 times , you should be able to kill them with one shot. Kill around 500 of them, and you should be able to go up around 15 levels.

Part credit to coolgu2k5 for correcting part of the tip