I'm not a huge fan of introduction videos, because they usually talk about what you're going to do instead of just doing it.
As mentioned by NickTF, try and figure out how to get rid of those black bars around your videos. People are much more likely to stick around if the audio/video quality is on point. However, even with perfect audio/video, it won't matter if your videos don't retain your audience's attention. It's important to keep the video moving along and make sure everything has a purpose. There was a big chunk in the middle where you weren't talking and I wasn't sure what the point of it all was. If they're supposed to be funny clips, make sure you enforce that with some silly music or graphics.
Another thing you can do to keep the viewer around is to amp up the energy. Your voice sounds a little dead and unenthusiastic. This is something that will come with time, but just be aware of it when recording. You don't need to sound like someone working for Disney, but make it sound like you're more interested in what you're talking about.
If you want to get better, just keep making videos. It's just like anything else, it takes practice.
Edit: Oh, and be yourself! That's a big one too.
