These are tricks specifically for improving your ICC Raid time.

Glider Glitch: This glitch with normal gliders has been patched out, however, you can still fly through with the Demon Hunters glide.

This glitch allows you to bypass a miniboss, the Dreamwalker boss fight, and a timed miniboss-esqe horde mode. It will take you directly to the Sindragosa fight, and upon riding the elevator back up, you can run straight into the final teleporter to the Crowned King himself, Arthas.