I have a huge headache from a week's worth of trying to get JSPs and servlets working on Tomcat. Wouldn't you know that 3 hours after I finally got it working I ran across this article which explained most of the procedure? I wish I had found it earler, and I wish other resources had been half as useful.
My only suggestion, and it probably wouldn't really fit into the size constraints of the article, is just a few troubleshooting hints, e.g. for the ubiquitous "Requested resource is not available" error. Once you've convinced a reader to try out a new technology it would be good to leave them a few tips for the problems that they'll inevitably encounter.
But, like I said, this was by far the best resource I've come across in a week's worth of searching!