I took a look at your flickr images. I don't think the issue is whether or not your technical abilities (i.e. exposure) are at fault. I think you need to analyze how you interact with your subjects and learn how to make them feel more comfortable so that they look more nature through the camera. That is far more difficult than mastering the technical details.

However, if you do want to fine tune your technical skills, I wrote a thread about it some time ago here:

The 4 Basics