Start mining with a load of workers and get gas a.s.a.p. Build up the tech tree and make sure u get a hydralisk den and ultralisk den and a defiler mound. Get all upgrades for ground attacks and ultralisk upgrades and hydra upgrades. Get the defilers special plague ability and extra power cuz youll need it. Mass up on hydras and ultras. Send in 3 defilers for faster destruction and use plague on where there is a hot spot of defence if there is one.If there isn't one just use it where there are important buildings.Then use swarm all over the place and send your attack. When you probably get into his main base morph your hydras to lurkers and use plague in the last spot(probably the mineral feild)and burrow your lurkers to finish it off and ease the pain on your opponent.

CreepColony's Opinion: I think you should just bring lurkers in instead of hydras because if you dark swarm everywhere you hydras won't be able to hit anything.