Super Mario R.P.G
Peachy, the Battle Tank
When you find the Lazy Shell armor in Rose Town, equip it on Peach. While her attack and magic attack will fall by half, her defense will double. Peachy is the best one to put the armor on, as her "Come Back" move is unaffected by the decrease in magic attack power if you time it correctly. With the armor on her, she will rarely ever take more then 3 damage points per attack, even from the Axem Rangers, or Smithy.
Yoshi Without Eyes
On Yoshter's Island, hop onto Yoshi’s back. Turn Yoshi so that he is facing the camera. If you look closely, you will notice that Yoshi's eyes are missing.
Contributed by Schuyler
Defeat Johnny Easier
Normally, when you fight Johnny, mid-way through battle, Mario will have to fight him one on one. With this trick that won't happen and you can defeat him with all three characters in your party. When you battle him, instead of destroying his little shark helpers, just aim for Johnny himself. Eventually, you'll defeat Johnny without doing it one-on-one, its a lot easier this way.