The Reddit Giveaway posts are working, but also bringing a lot of people who will come for giveaways, then leave.

If you've not already, post a few recordings of the Stream with popular games on Youtube. Link to the stream.

Maybe take out a cheap web advert on a gaming site?

Dishonored - but to be fair that's because I really want it myself and I saw it listed under current games on the channel.

Trials Evolution: Gold Edition - after the full release anyway. The beta is pretty buggy. It's fun to watch and play.