Play with one character as Huang Gai and the second player as the character you want to work on. Make sure you are playing on an easy level, such as one of the Yellow Turban levels (because allies are not really needed there). Have the player who is not Haung Gai stay close to him, as the power-ups eventually fade away, and it also saves time. Go near an allied General with Huang Gai. Lay two bombs next to him by pressing Triangle(2). Run away before the bombs hurt you and repeat. The allied General will have 1 HP remaining after you repeat the bombing. Wait for the general to be hit once by anyone, even peons. The General will die, leaving a power-up. It is not a good idea to do it to the commander, considering he or she needs to stay alive or you will lose. This works on any General, friend or not. It also affects your bodyguards; keep them away from the bombs. Put your bodyguards to hold position by pressing Select.