To get Mimitchi, you really need to keep him with you at all times. Same goes for Mametchi. Keep checking every half hour or so to make sure you don't lose any hearts. It's easier to get a young mimi than an adult. Just don't forget him, and you should be able to catch him when his hearts deplete by one and when he beeps for discipline. Play both games, and score well on them. Yes, you need to play dance at least once. Also try putting him to bed a half hour early. Toddlers and and young mimitchi go to bed at 8, so at 7:30 you can put them to bed, which gives a happy heart. I have gotten mimitchi from oniontchi, so don't despair if you have oniontchi. Just take perfect care of him, fill a heart as soon as it empties.