Pickup games?

I find when I jump into the 1v1 room I can get a game within 10-15 minutes (someone else will hop in to join me).

Though I'm assuming you have done that already.

Typically I've found 2PM-7PM PST (10PM-3AM UTC) to be quite active, though that's probably not the only time.

Also, when I wait in a room I tend to just hop into a room, pick a map I like, and then do other stuff on my other monitor, glancing back every couple minutes in case someone comes in. If you don't have multiple monitors, the lobby tends to flash in the taskbar when someone speaks. I'm not sure if that counts join/leave lines when those are enabled, but enabling those for battle chat might work in that case.