If you do stream, do it right:
-Make sure you don't have microphone noise
-Have some sort of intro or at least screenshots on intro
-Have something for intermissions
-Most importantly, make darn sure you can actually handle the upstream load of spitting out ~2-3 mbps worth of video and audio, as well as the CPU load of compressing it on the fly.
I've found a lot of people get lots of lag from Twitch when I stream at the recommended maximum of 3500 kbps video, so I've dropped mine to 2250 kbps with a more processor-intensive h.264 profile (to reduce the motion artifacts at lower bitrate), but that's on a 3.8GHz i7-2600k (the stock OC settings) and even then it is only at 30fps.
Of course, the other side is commentary. My biggest tip is to avoid any audible pauses (ex. "uh", "um", "er", etc.). Beyond that is just a question of finding a style that is entertaining and natural to do.
As for advertisement, I'm not sure. I've been steadily growing a follower-base over the last few months, but I'm only up to 41 (most people seem to prefer YouTube at this point). I would imagine primary marketing would have to approach from a different angle for Zero-K streams to get good visibility, though after that streams would probably be a useful point of entry for people.