Usually (probably always I hope) when troubleshooting production environments we don´t have Visual Studio or other “nice looking” tools to help us finding problems. But we have one of my favorite tools: Windbg.
The first time someone showed me Windbg and all the stuff around production debugging like memory dump, … I was a little (maybe not just a little) scared on this new world that had just opened in front of me. So my next question was: where do I start from? And probably like almost everyone that starts exploring this “new world” there are excellent blogs like http://blogs.msdn.com/tess (If Broken it is, fix it you should), http://blogs.msdn.com/dougste (Notes from a dark corner), http://blogs.msdn.com/tom (ASP.NET Debugging) and many others.
One of my biggest problems at first was to understand (and remember) what and when I should collect information that could help me to troubleshoot the issue. The blogs above have a lot of information about taking the first steps. To simplify this task I´ve created a little graphical memo that would help me. Now don´t take this flowchart as the “holy grail” but I believe it can help (at least until you get the basics in your mind).
Right click on the image to save it and it will be more “readable”.