How can I determine if wires are live and test them safely?

To determine if wires are live and test them safely, use a non-contact voltage tester or a multimeter. Ensure the tester is working properly before use. Keep one hand in your pocket or behind your back to avoid a shock. Approach the wire with the tester and observe the indicator or reading to determine if the wire is live. Always follow safety precautions and wear appropriate protective gear when working with electricity.