Advantage signal

When you give an advantage, when should you give the signal? Is it while you are thinking about giving an advantage? Or is it while you are waiting and seeing if it materializes? Or is it after it actually materializes?

The best practice is to give a signal when an advantage actually materializes. This will prevent an awkward sequence of the referee giving a signal only to call the original foul. Instead, keep observing and asking yourself if an advantage is a better option than a free kick without giving a signal. Once an advantage materializes, then give a signal.