From what I've seen & heard, the only way to get guaranteed tickets to watch a DWTS show is through charity auctions & the like. The general tickets require that you wait in line for a 1st come 1st serve seating...meaning you may not make it.
I thought it might be nice to create a post/thread where people can list any charity related auctions they're aware of that will afford people the chance to see a live taping. I just learned about one that's going on now (I can't attend to bid) & I figured I would pass the info along.

Ken Mar Animal rescue is hosting a 4hr celebrity Wine, Cheese, & Chocolate charity fundraiser Saturday November 13th on an estate in the Hollywood Hills (Tickets $50). The event includes a silent auction where one of the items is a pair of VIP DWTS tickets (show taping November 16th). The event will have guest celebrities from Chuck and the Young & the Restless, if you're fans of those shows as well. Details here if you're interested…I’m pretty sure you have to attend the event to bid on the tickets: http://tinyurl.com/283hub2