Sounds like you already have a following, that's a start. If your video blog content is similar to your other content, anyway. If not I suggest you start a new channel. Don't worry, you'll find a niche.
The best advice is to be active in the community. Don't sub4sub, this doesn't work. Instead, work on getting a few people who really like what you do, and answer them in your comments and make friends with them.
Get your real life friends to help you out. Remember, if they like it, they might share it with their friends.
Ask questions to provoke comments, then answer those comments. This keeps people coming back to your videos.
Update regularly, people are creatures of habit.
Always be friendly.
Try to have a theme to your vlogs (this also works with blogs). If you're a tech guy, discuss tech. Even if Chris Pirillo's already got tech down, people will appreciate a new spin on it, or at least a new face.
Find something you're passionate about and go for it. People respond well to passionate people.
The first vlog is always the hardest. After that, you'll learn new tips and tricks to help you get better every day! Remember technology is growing and you are always learning. Don't be afraid to try something new. Your viewers will let you know if it works for you.
Remember this forum is a great place for feedback. If your viewers aren't leaving enough comments. Don't be afraid to post a link here and ask for more advice.