This works for any class with water walking, you can also buy water walking potions off the auction house.
If you're defending in Strand of the Ancients, right when the game starts put water walking up and head for the water. Once you're at the docks (Either one, it doesn't matter) mount up and walk across the water to the boat. Get in front of the boat, stop walking, and dismount. The boat should run over you, and you can jump to get stuck in the bottom of the boat.
A couple more jumps will get you in the lower part of the boat, go up the stairs and you can find the enemy grouped up on the top of the boat. At this point I usually use blast wave on my mage, half the team gets knocked into the water, and they have to swim back to the shore. To make this better, get to the boat as fast as possible.
Hope someone finds this useful.