When you get into the Glitz Pit, fight until you are near rank 7 or 8. You should now be fighting 'the fuzz'. Kill the black Fuzzie that has 3 HP then kill the Flower Fuzzy (pinky). Next, keep the green one near 1 HP remaining. He will split in two. Kill one of them (always leave one alive). It also helps when you have Koops out for a partner. Just leave Mario in front and Koops in back and use his Shell Shield (new attack when you upgrade him). Every time that it breaks, put a new one on. It helps to have some Happy Heart or Happy Flower badges equipped. Keep doing this and you can get 50 Star points in about five minutes.