Not to argue with anyone but I've backed a lot of otome games, I also looked at the campaigns for even more otome games. The number of tiers for successful campaigns tends to be 8 to 20 (some even went up to 30 omg) so do what you want in terms of tier numbers. Something I've seen almost universally in game Kickstarters is a limited number (often about 100 or so) of lower priced "early bird" priced tiers that are a dollar or so less than the regular that will be available when the early bird runs out. I wouldn't make the early-bird price lower than the currently listed price though (you can go higher but I really don't think you should go lower). I've never seen a game kickstarter offer the game for less than $15 USD and that was for the limited discounted ones $15-25 or so seems a good price but up to you.
Edit: I would keep the one dollar pledge but those usually have no rewards.