The first time I played Mario's Rainbow Castle, I thought that this level was impossible. I mean every time I would get to the tower, Bowser would always be there. So I finally started getting some stars, and figured out that it wasn't impossible. But here are a few tips. First, always, without fail be the first one up there. So you're guarnteed to get the star from Toad. And when you get the star it makes the next person get Bowser. Now the Boo encounters. there is only one Boo, if you go left in front of the small tower, he's right there. That's about all the advice I have for this.
Peach's Birthday Cake is a COOL level. it has so many various things that can happen. So start and circle around the cake. If you land on a ? space, then someone will ask you if you want to plant flower. I would suggest not, because it cost 30 coins and it is highly unlikely that someone will land on it. Oh yeah, if someone does land on it, if they have a star then they give it to you. I don't think there is a Boo, but their might be. And when you have the seed thing, choose the blue seed, it will send you the right way most of the time.
Luigi's Engine Room is a hard level to get stars on. Everything matters on what doors are up, when they're up, what you roll, and which way you choose to go. So you start out when you get to the first crossroad, don't go down, unless you need to change the doors. Otherwise go up, one, because you don't have to listen to the pipe, and two, it's quicker. tehn, you're on your own, the next crossroad you go to depends on where the star is. Oh, and by the way, all the pipes lead to the one by the boo. And also, when you get to the big crossroad, if you go left, Bowser is over there and you'll lose 19 coins.
D.K's Jungle Adventure is one o the funnest levels, but also one of the most depressing levels, and it'll make you say, "but I almost had it!" So put your thinking caps, on a-, wait a second, I tell you what to do, and you just do it, so, all you gotta' do is remember this. So remember this. So you start out, on the first place with the Thwomp, (big rock guy), go straight, never ever go left. But on the second one go left, unless the start is on the straight path. Go left because if you land on one of the ? spaces, it'll send a boulder down the path and chase you back to start. So continue and go to Boo. What you do is your choice, but keep in mind, there are two Boos. And the rest is your choice, all depending on where the star is. So good luck!