I don't think I can help you there although I've heard there are certen things you do as a baby, kid, and a teen to get that. I've heard that you feed it at certen times with certen foods or play a game at a specific time. Don't worry, you'll get one eventually.
It has to be on an even generation, and try to take very good care of it. That was how I got one, but their is no instructions on how to get a certain character that works on every tamagotchi. Just try your best and have fun with every character you may get. :furawatchi: