Leveling up in Zelda 2

Make sure you have very few points right before returning the crystal to the palace. Returning a crystal automatically takes you to your next level. So, if you are only a few points away from your next level up, kill a few more enemies first to reach that level before returning the crystal. Otherwise, you waste a level up.

This is perfect advice! I personally need every level I can get in this game! I'm the type of person that would level my attack up to level 4 before even entering the first dungeon normally... unless I have an audience XD