Turn off power to the circuit before testing
Set the circuit tester to the correct mode if needed
Check the tester on a known live source first
Touch or connect the tester probes to the test points
Observe the tester indicator, light, display, or sound
Compare the reading to the expected result
Test both sides of the circuit if necessary
Move the probes carefully to avoid short circuits
Keep hands away from exposed conductors
Use insulated tools and wear proper safety gear
Turn power back on only when testing requires it
Recheck the tester on a known live source after use
Store the tester properly when finished