The jumping rope, mimic, and dance game helps.
Also, have your Tama eat cherries, cheesecakes, cupcakes, donuts, and also melons and yogurts.
When you get invited to primary school, as soon as the turtle teacher appears, press A. Then you'll get a teacher looking like a flower, and she'll give you "flower points" when you find them in her present game.
Also, welcome to TT! Please, enjoy yourself and call me if you need anymore help!