Be prepared-remember that good troubleshooting requires a thorough understanding of the basics.
The service engineer should know the normal system operation, since a large part of troubleshooting is visualizing what is happening throughout a system.
One tool to aid the troubleshooter in understanding the system is the electrical flow chart provided by many equipment manufacturers.
Avoid the bad habit of skipping steps in the process.
Try not to draw quick and usually inaccurate conclusions before a complete analysis.
For the testing process, good, reliable test instruments are among the most valuable tools that any service technician can have.