In Hyrule Temple, try to stay to the left at the top. You can get back on at the bottom if you're knocked off.
In Green Greens (either one), use the tree's wind to force enemies off.
In Brinstar, knock enemies into the lava.
In Peach's Castle, Banzai Bill does a lot of damage when he explodes.
10000 posts at last! w00t! Okay, I'm off into a quiet retirement. Don't bother me.