Go to the level entitled Makin’ Waves and obtain the Clock item. About a quarter of the way through you should see a ramp and a guy in a rowboat. Go on the ramp and land on him to get two lives. However, you must kill your character to keep getting more lives. Since you get two at a time, you can slowly but surely build up your number of extra lives. Remember; get the Clock item, get the lives by jumping on the guy in the rowboat, kill your character, and repeat.
Go to level 11, Dino Might, and go into the gold gem path. Follow the path until you get to the pterodactyls. Pass the first one and, when you get to the second one, jump into it to be transported to a level where you ride the dinosaur through the entire level.