Always nice to see a well written set of tips. These are good ones. I've never come across Fiddler before either!
http://blog.thekid.me.uk/archive/2007/07/25/debugging-tips-for-sharepoint-and-wss-exceptions.aspx
I must get my feeds updated with more good quality blogs!
About hangseesing
I'm a Software Engineer by trade, the last few years I've been involved in a large public sector organisation as a Solutions Architect. I specialise in Sharepoint and related technologies.