If your network troubleshooting is more art than science, then you might need to try a more methodical approach. Here is a basic guide that will help you organize your troubleshooting efforts.
When troubleshooting network problems, you might follow a trial-and-error approach that eventually leads you to the answer, but a more organized method will save you time and make your troubleshooting more efficient. Global Knowledge provides a guide, "TCP/IP Sleuthing: Troubleshooting TCP/IP Using Your Toolbox," that offers a concise troubleshooting methodoloy, based on the OSI model.
The OSI model divides the network architecture into seven layers:
Layer 7 Application
Layer 6 Presentation
Layer 5 Session
Layer 4 Transport
Layer 3 Network
Layer 2 Data Link
Layer 1 Physical
This handy 13-page white paper outlines troubleshooting tips for each layer using common network tools such as ARP, ping, NETSTAT, and protocol analyzers. If you need more method to your madness, download this guide from the TechRepublic directory.