If you plan on making more youtube videos with your voice in them, investing in a better or mic and/or working on sound levels would be a good idea.
Also, when looking for a tutorial for something, I usually avoid video tutorials as they can't be skimmed for the information I need. Instead of just finding what I need and leaving, I have to watch the whole video to fix my problem. (and often mute them for the reason below...)
I would suggest using videos as visual aid and/or typing the tutorial out instead of explaining it orally. Screenshots would help a lot too.
I also avoid watching video tutorials because many of them are incredibly boring and the voice of the person talking is annoying a lot of the time because of the way they talk.
I had to turn the volume on my laptop up to 80% (It's usually between 10 and 30, occasionally 50) to hear any sound in the video as well.

Famous youtubers generally are great at tutorials and things because they've had practice talking to their computers.
I've watched videos about minecraft mods, a new snapshot, or just a tutorial for doing something in it and often have to mute it. Just seeing what they're doing on screen is enough usually, and watching a different video for basically the same thing, but by the Yogscast, it's so much better because they also make it entertaining.

I understand how hard it can be though, because I'm too easily embarrassed to let anyone on the internet hear my voice at all.
I could have sworn I had more to say, but I've forgotten...
Anyway, you know what I suggest and I hope you get better at this stuff