What is the Best & Efficient Electronic Circuit Troubleshooting Techniques ?

Verify the symptoms, Locate the module and Start to trouble shoot from output to input side.... :)

There are multiple you can start from multimeter

1.  understanding how the circuit working
2.  familiarity with electronic components exist at the circuit
3. ability to test the electronic components
4. ability to specify the problem in the circuit and test the area of this circuit cause problem
5. sometimes with eye vision problem can be seen and blown component can be replaced