There are those gray things to shoot mario. You will start in this course moving with gray things and then, with those starts that grabs you as well. Well... after that (after you passed some mines) you will see a sticky gray thing. When you see it, die (by this way is easier to explain)

Now, you will start grabbed to the gray thing, on your left, there are white star bites coming, grab all of them (there are around 44-46) Then, instead of shooting to the second gray thing, shoot at 3:00 (if you move grabbed to the thing you will see it) There is a huge coin. After shooting, click on the star, as you will fall if you do not do it. Now keep going, the coin made like a road of white star bites (so grab all of them) You will grab around 60-70 star bites (which, added to the previous one, makes more than 100, so two lifes) Keep going and you will see an arrow made of red star dust (do not confuse!!! there is a second arrow, it's not the first one!), you will grab most of them (20-40) then, you will see the star at the end (need one shoot more) grab it if you did it before, if not, just shot away throwing poor mario to the black hole)

Repeat the action
Repeat the action
Repeat the action
Repeat the action
Repeat the action
Repeat the action

In 5-10 minutes, you will have around 1200 star bites and 7-8 lifes more.

110 star bites
2 lifes (from starts)
1 life (from a mushroom, you will see it, you can die there)

You only can get 999. So you must complete the course and start over if you wanna more