Final Fantasy 2 Codes -

Easy HP and Strength:
Go into battle, against Imp or another easy monster. Hit yourself with two or three of your characters, and cure with the other one. Do this a few times, then kill the monster(s). You will gain HP and Strength, which is an easy way to built up a character at the start of the game.

Easy weapon experience:
To easily gain experience with a certain weapon, get two of the same weapon. Equip both to one person (left and right hands) and fight monsters in the area that you are in. You will get experience for each time you hit with that weapon. The same thing happens with a shield, but with a shield, you cannot attack with it.