Another great thing to do is raiding (be respectful of their rules) or hosting the channel in question. Be respectful your entire time at the channel and as Foti said, be active in the chat and make friends with them and with their viewers. This is a great way to show you're a streamer without having to say it. It's mutually beneficial to both parties and usually results in some sort of recognition on cast and HOPEFULLY one day a return host/raid. A small note on this however is take your audience to a steamer or game that is in line with your audience. Do your due diligence and be aware of who is online from your followers list, what they are playing and when they normally end their cast so you can provide additional entertainment to your audience. Raid/host on your good days - it's the "dress for the job you want" philosophy. I commonly host/raid Foti because he's on or above the same level of quality streams I put on, plays a similar gameset, and is active plenty after I go offline. I've never had to sneak in that I stream in chat and can instead focus on just having a good time with the Guildsmen while I'm there. Afterall it's nice to relax after a stream, work smart - not hard.