Get a friend on steam, go to their game info and click join game. It'll say server is full and show a menu saying "Rejoin when there's a space" or something like that. Then steam will join the server whenever a space opens up.
I would go to Legacy browser, and connect there, and if it says, "server full" I set it to "join server when player slot available"
This gets me in within 3 minutes sometimes.
While waiting I listen to Green Day songs, good band...
I mainly just sit there for 2 or so minutes spamming the 'Join Server' button while holding down the 'Enter' key. It's pretty efficient, sometimes however it doesn't work as good.