The most effective way of making yourself better known is simply to keep making good videos. A good kickstart, though, might be making a thread up in DF Dwarf Mode discussion.
Onto the actual quality of your videos; I've not watched much, just the first couple of minutes of number 7, but here are my impressions:
-Your voice isn't hard/annoying to listen to, there's a kind of echoiness in the audio but it's not a huge issue. SOmetimes, an otherwise great series is ruined by someone's commentary being painfully low-quality. If you do get at all big, I'd recommend buying a dedicated mic, but that's a ways off for now.
- Minor thing, but it might look rather more professional (and possibly save you some privacy headaches) if you crop out the taskbar and the bar at the top of your screen; they're mostly distractions from the actual content.
-Last thing, probably the biggest but hardest to do anything about, is learning to keep up a continuous stream of commentary without umms and ahs (or just silence) dominating. You're reasonable at this already, but still have occasional points that bring the watching experience to a halt. In general, try to have an idea of what you're doing next. If you have to pause recording and think about it offscreen every few minutes of video, that's perfectly normal and could be very helpful.
Good luck, mate.