Color Grading?

I want to understand and practice how to better my video's appearance. Where do I start to understand 'color grading'? or other post production techniques in editing image quality.

I use Sony Vegas 7e Pro.

colour grading is as much an art as it is technical skill. I would start by learning how to read your vectorscope and waveform monitor. These are like the video equivalent of a histogram. Of course it also helps a lot if you have a television preview monitor attached or your computer monitor is regularly calibrated. I would also recommend you google video demontrations, there are plenty around, although after effects seems to be the tool of choice, i think basic grading can be done of vegas.

sometimes it can also depend on what type of grading you going for... google is probs best option, can learn yourself