How can I get over that VO awkwardness and get more energy?

I think I have quite a good technical grasp of video making, but the one thing that really holds me back is my voice over. I can feel it just being dull and boring, it's slow and monotone and dry. Normally I'm a really quick speaker and I mumble a lot, I also have a Yorkshire accent (think Sean Bean) but as soon as the mic is in front of me I start talking the Queens English really slowly. Does anyone have any suggestions because I know think at the moment it's holding me back. I want to try being dry and sarcastic, but the style of my videos doesn't really suite that as they're already pretty slow. Any help much appreciated, cheers.