Vlogging is quite straight forward when you think about it. All you need to do is put a camera facing yourself and talk for a while. I used to have the same problem, what do I talk about? I just talk about what I have done in the past week or so; maybe chat about something which is coming up, explain how excited or nervous you are feeling about it. Some editing tip could be that you could add music over the vlog. It adds a finer touch and professionalism to your video. Try not to say 'urm', try and have a little script that you can stick to.

Hope that helps, any more questions I'll try to answer!