Step 1: Prepare
Every human activity requires preparation. In troubleshooting, one must prepare his tools, work area, documentation, and most important, his attitude.
In troubleshooting, as in any other human endeavor, you must have the right attitude to succeed. You CAN solve it. It's not magic -- there's always an explanation. Don't try to fix it, just try to narrow it down. Don't panic. Don't get mad. Be patient and don't skip steps. Practice teamwork. When you get in a bind, just ask yourself "how can I narrow it down one more time?". Or in a bind, devise a distinction-finding matrix involving "is" and "is not" questions in the realm of "who", "which/what", "where", "when", and "to what extent".
The best way to get and maintain the attitude is to remember that it is a mathematical certainty that you will solve any reproducible problem in a system for which you have knowledge or system documentation. To see why it's a mathematical certainty, review Step 6, then click your browsers "back" button to return here. Above all, remember that your troubleshooting power comes from your troubleshooting process.
See the following articles for more on The Attitude: