List three strategies for seeing that your guests do not leave your home or residence while impaired

Have one person be the bartender, and keep track of how much people drink, and then limit the amount of alcohol people consume. Serve no alcohol or have only a limited amount available, while having a wide variety of nonalcoholic beverages available. Declare in advance that this will be an alcohol free event and that you will provide beverages that are nonalcoholic, and would like guests to respect that and not bring alcohol.