Start out by heading to the right past the Goomba and wall jumping up to the swing above. Swing and jump across the gap, then continue right past another Goomba to some more wall jumps. Keep heading up and grab the Bee Mushroom, and fly up to the checkpoint. Keep going up and to the right until you reach a set of clouds and three Choppas. Use the clouds and the flowers to get up above them to the wooden walkway, which will take you around to a couple slide vines. These drop you off in a section with more clouds, a couple Choppahs and some huge grapes that you can bounce off of. The ? Coin here creates a circle of coins in the air and if you collect them all you'll get a 1-Up. Make it past the second Choppah and you'll get another checkpoint flag.
The next section goes upward with orange posts you can climb on and Fuzzys on some of them. Avoid the Fuzzys and the Choppah above and take the set of swings over to another set of slide vines. These take you to the next checkpoint, after which you'll need to fly to the right while avoiding the spiky plants that snap at you. Fly above the first one, then quickly get between the next two. Don't rest for long on the purple flower with the green underside, as it will snap you up. In the next area, quickly jump down the flowers to the bottom where the grapes are, then go back up to the right past the last spiky plants out into the open. Get on a cloud out there as quickly as possible so you don't have to stay on one of the snapping flowers. Here you want to either go under the Choppah and fly up to the next cloud or fly over it when it's down low. From the second cloud you can easily fly up and grab the Power Star.
The Secret Wall Jump (Hidden Star)
Start out like normal and go up to the first swing in the level. Instead of swinging to the other platform, swing high enough to the right so that you fly up to the wall that has wood embedded in it. From there, quickly wall jump until you get to the very top of the area. The Power Star will be there waiting for you. When you finish this level, a bee will appear on Starship Mario.
The first Green Star is in the area with the grapes and the ? Coin. Jump on the small grape next to the second Choppah and you'll easily have enough bee power to fly up to it. After the section with the orange posts and Fuzzys, jump up onto the wooden post the second swing is hanging from and fly out to the right over the slide vine to find the second Green Star.