When you perform the following 6 actions during the game you will be able to gain the indicated amount of extra lives.
1) Jump on 7 turtles to get an extra life. If you are fast enough you can keep jumping on the turtles until there are no more to jump on.
2) Go to World 2-3. Just before the flag are some stairs with a turtle moving down. Use a precisely timed jump to continue bouncing on it's shell to collect up to 99 lives.
3) When you are riding on a Yoshi jump on the bullets 7 or 8 times to get as many extra lives as you want.
4) Kill 8 enemies with a star on you to get an extra life. If you are fast enough you can keep it going until the star runs out.
5) Kill 8 enemies with a turtle shell you will get an extra life. If you run fast enough you can keep hitting the turtle shell until there are no more enemies.
6) Freeze the Pokeies then do a quick Ground Pound to get at least 5 extra lives.
Added by: Sanzano Mar 12th 2010, ID#3565