Go to any Bowser the first will be the easiest. Don't kill him but run around and let him spit fire at you. When he spits fire he will drop coins. Collect these coins until you get 1000 coins. An "M" will appear next to the lives icon. Exit this course and let the fun begin. Every time you die you will get a life but beware if get a 1up you will lose a life.
Submitted by Bhb111
When you go outside in the moat emptied go under the bridge and you'll see coins directly underneath it. Do a triple jump to one side when underneath and on the third jump wall kick to the coin if you get both of them a mushroomlife appears.
Submitted by Dylan Smith