What is a good technique to use when trying to determine if a customer is intoxicated

Techniques in determining the intoxicated customer:

The process of intoxication identification means to identify whether a person has consumed alcohol or not.

In order to identify the following techniques can be utilized:

Communication is the best technique to identify as drunkard person has certain changes in the mode when compared to the normal person. Observing the suspected person for their behavior with others in the surrounding area. The common signs of identifying such persons are slurred speech, loss of balance, shouting and self-speaking.

Give them beer for free if they get it they are intoxicated if they want to pay not