1) The Red Coins near you should be a start. Then go for the hard ones, the ends of the birds. Then wait for a while and go in front of 1 of the sand blocks sticking out. When the bird turns, you should be on the sticking out sand block. Then it will go back to normal and then get ready to jump and hover for the coin which will take long (which is to your left).
2) That's a challenge. You have to be very careful and be on the look for the coins (use the C Stick for better looking around). Try not to miss a coin.
3) This is easy and fun at the same time, and a time to practice your FLUDD technique's. First spray around till you find a barrel and carry, then throw it to an area with lots of goop. Then use these techinues after the barrels are gone:
-Rotate Control Stick and Spray Water (while on ground).
-Jump, then Rotate Control Stick and Spray Water (while in air).
-Jump and Spray at the same time which should let out bursts of water.
-Spray, hold L, then jump which should flip backwards and spray at the same time.
-Spray while running, then do the triple jump and you should flip forwards and spray at the same time.
Use these to clear the beach in no time!
4) This takes skill and patience.
Get a durain (since that's the only fruit to get) and it takes a while to pop 1 out of the machine. When you do, carefully kick it to Yoshi. Don't run or it could go into sea. Then when you get near a fish, spray the fish as soon as it jumps and gets to the highest point. It should make a platform for jumping. Keep doing this to get to the Sunshine in the Cage. Then Juice it and it should open it. Then get in the cage and get the Sunshine Sprite to win the level.