The best advice I could say would be to think of more to talk about. I've watched a couple of your videos and you're very quiet...and in my opinion, isn't a good thing. Think about rendering your footage beforehand and doing a voice over commentary. Most people who subscribe to Let's Play channels do it for the person's personality. It doesn't matter if you have Skyrim and MW3 Let's Plays out if they're no different from the other 400 I've seen in the last few days. That's probably the thing that I'd stress the most...just TALK. And not about the game either...I mean you can, but even that gets boring after awhile. Follow the examples of the other gaming commentators you watch, figure out interesting things going on in your life, talk about current events...but if you JUST play the game...most people will just go to the next video.
But that's just my two cents, take this as you will.