Super Mario Bros. 2 (NES)
Pause the game, then hold Up+B+A on Controller II. Unpause, and your character will instantly lose a life.
A small heart will appear after every eight enemies you defeat in a level. Collect the heart to refill one empty piece of your life meter.
Usually, you get two coin-collecting chances per level from Sub-Space. But if you die while in Sub-Space, it doesn't count as a complete Sub-Space visit, plus you get to keep any coins you collected! Using this trick, you can really rack up the coins for tons of Bonus Chance tries. This is useful if you're really good at the Bonus Chance game.
Warp to World 4
Take a Potion in World 1-3 over to the vase sitting beyond the brick wall. The Potion under the log platform is a good choice because it is closest to the vase. Drop the Potion near the vase, enter the door to Sub-Space, then go down the vase to warp to World 4.
Warp to World 5
In 3-1, enter the first door, then jump down the waterfall (trust us). Stay in the center of the screen as you fall, and you'll land safely near another door. Inside, grab the tenth clump of grass and take the Potion to the vase, which is a little further ahead. Go down the vase while in Sub-Space and you'll warp to World 5-1.
Warp to World 6
After the first group of whales in World 4-2, grab the Potion from the seventh grass clump. You'll have to carry it for a while until you find the vase. Drop the Potion when you're on the same platform as the vase. Take the door to Sub-Space, then go down the vase to warp to World 6-1.
Warp to World 7
Choose Luigi for World 5-3. At the start of the stage, climb up the ladder, then power jump up to the vase. Pull up the Potion from the rightmost clump of grass. Go down the vase while in Sub-Space and you'll warp to World 7-1. If you don't pick Luigi, it's still possible to reach the high ledge by hitching a ride on an Albatoss flying left.
Toad actually runs faster when he's carrying an object. Another tip: If you released the B button for whatever reason, you can pause the game, hold B, then unpause to run again without throwing away what you're carrying.