Super Mario World

Hint: Extra Lives - First Ghost House
In the first ghost house, fly up to the upper left corner. You will see a ledge. Run to the right and you will fall. Ghosts will try to hurt you but keep on going. At the end of the ledge you will fall and there will be four extra guys. You will have to hit the boxes to get them. Go though the door. There will be a Moon (3 lives.) After you beat it there will be a level above the ghost house. Go to it. In it there is five boxes. The two left ones contain, flowers. The two right ones contain feathers. The middle one has Yoshi. If you already have Yoshi then it will be an extra life. To exit, run off the screen.

Hint: Extra Lives - Vanilla Secret 2
Enter Vanilla Secret 2 and get to the half-way mark without killing any Koopa Troopers or the green jumping guys. Keep on going until you reach a pit with a lot of spinny orange guys. There will be yellow blocks right above the pit. Hit the blocks until you get a silver "P" switch.
Carry this switch a little past the half way mark until you reach two pipes with red guys jumping out of them. Put down the "P" switch, step on it, and run back to the start of the level. While your running there will be a lot of silver coins on the way. Get all the silver coins you can and you will gain 50+ lives!
Important: Be sure not to kill the Koopa Troopers (or the green junping guys) on the way to the "P" swich, those guys turn into the coins that give you the lives.

Back Door Bowser
On the map screen, you'll notice that Bowser's castle has two doors. In order to access the Back Door, you must first go to Valley of Bowser 2, equipped with a Cape Feather. After passing through the moving horizontal rocks and going through the yellow pipe, there is a long passageway consisting of a moving rock formation and a flying '?' Block. (If you are equipped with a Yoshi, do not hit the block, because it contains a pair of wings, causing you to bypass the whole level.) When you pass the moving corridor and go through the green pipe, there should be a yellow rock floor. (You must run past this before the rock crushes you.) Simply fly onto the brown ledge above said rock, and move left. A short drop will lead you to a key and keyhole. Pick up the key, insert it in the keyhole, and you'll be warped out of the level. This action will reveal a path to a Fortress on the map screen. Defeat the Reznor, and a path to Bowser's Back Door.