Some of difference in alcohol tolerance may also be attributed to a person' genetics or family history. Some research suggests that people with a family history of alcoholism may have a higher tolerance than normal. Of course, health can also play a large role in how a person experiences the effects of alcohol.
To reduce alcohol tolerance, a person needs to reduce the amount of booze one drinks. Refraining from drinking will lower the body's AT level. As a result of lowering the tolerance, one will feel the effects of alcohol after consuming smaller quantities than before.