This was a bit ambiguous to me, that is, when I first heard I needed to be dominant. But now, I am really starting to understand. A quick elucidation by example. I open and chat up a girl for a few minutes, she says she has to get going and starts to walk off, to which I reply "Whoa whoa" while grabbing her arm and pulling her back in as she turns around to walk away, "this isn't over yet". I've noticed any sort of dominant kino like this really ramps up the attraction fast.
Another similar example. You are speaking to a girl at a party and find her difficult to hear. Instead of you leaning in to her, you grab her arm and pull her in close to you, so your faces are nearly in contact.
I think a crucial aspect to being more dominant is making more commands. For example, now, when I see a girl I think is cute and have spoken to before, I don't walk up and address her instantly with a "Hey, how's it goin?!" or anything like that. I look at her with a smile, stand/sit still, and say something like "Megan. Come here. Talk to me" or "Shawna. Get over here" with a very firm, solid tone and pull her in for a hug or something like that.
tl;dr Be a man, not a chode.