Lots of successful programming depends on how Good you are in debugging, everyone of us tends to make mistake while programming but if you are good in debugging then you can save lots of your precious time and frustrations. I found couple of good links which gives you very good understanding in debugging in .net technologies.
Links related to debugging/viewing ViewState
Related: ViewState property code snippet
I hope this will help you, if also know some good sites then do share with me here in comments.