-In battlegrounds surrounded by a wall, look at the ceiling for ledges that one worm might fit on. Ninja Rope up to that area and use a very powerful weapon, such as Nuclear Test, and use it with that Worm. That Worm will survive and you will win, although all other Worms will be sacrificed.
-To win a match, find a decent place to hide underground. Use the Blow Torch to get underground, then stay there and keep skipping your turn. Then watch your enemies blow themselves apart.