World 3-1
World 3-1 is the best place to obtain unlimited 1-Ups. Get to the stairs at the end of the stage and jump on the second Koopa Troopa. Leave it in its shell, then jump on the left side of its shell to knock it into the step. If your timing is perfect, Mario will bounce off the shell automatically and you earn unlimited 1-Ups.
World 3-4
Podoboos are shooting out of these pits, so proceed with the utmost caution. Time your jumps carefully and cross the area when the Fire Bars are pointing down.
These four Fire Bars are rotating in different directions. Needless to say, they are deadly! Stay to the left and observe them for a moment. Learn their patterns, then carefully jump ahead.
These pits all contain Podoboos and King Koopa’s fire breath is headed your way. If things get too hot, seek refuge in the small alcove to the right of the pits.