Because of the age requirement, students under the age of 21 will find it difficult to get actual bartending experience. Part-time or summer jobs as waiters' assistants or waiters, however, will allow you to watch a bartender at work and in that way learn how to mix drinks and perform other bartending tasks. Preparing drinks at home is good experience, although in itself it does not qualify you to become a bartender. Any part-time or summer job that involves serving food and beverages to the public will give you the opportunity to see if you have the right temperament for this occupation.

Further career exploration may include talking with school counselors, visiting vocational schools that offer bartending courses, interviewing bartenders, and reading bar guides and manuals.

Bartenders take orders from waiters for customers seated in the restaurant or lounge; they also take orders from customers seated at the bar. They mix drinks by combining exactly the right proportion of liquor, wines, mixers, and other ingredients. In order to work efficiently, bartenders must know dozens of drink recipes off the top of their heads. They should also be able to measure accurately by sight in order to prepare drinks quickly, even during the busiest periods. They may be asked to mix drinks to suit a customer's taste, and they also serve beer, wine, and nonalcoholic beverages.

A well-stocked bar has dozens of types and brands of liquors and wines, as well as beer, soft drinks, soda and tonic water, fruits and fruit juices, and cream. Bartenders are responsible for maintaining this inventory and ordering supplies before they run out. They arrange bottles and glassware in attractive displays and often wash the glassware. In some of these duties they may be assisted by bartender assistants, also known as bar backs.

Bartenders collect payment on all drinks that are not served by the waiters of the establishment. This is done by either keeping a tab of the customers' drink orders and then totaling the bill before the customer leaves—the same way the wait staff does for food bills—or by charging for each drink served. In either case, the bartender must be able to calculate the bill quickly and accurately. Although many cash registers automatically total the bill, the bartender must also have a good idea of what customers have ordered to help ensure the cash register receipt is correct.

Bartenders who own their own businesses must also keep their own records, as well as hire, train, and direct their employees.

Today, special machines can automatically mix and dispense certain drinks. They are generally found in larger operations. But even if they became more widespread, they could not replace bartenders. Bartenders still have the knowledge and expertise needed to fill unusual orders or to dispense drinks manually in case the automatic equipment does not function properly.

In combination taverns and packaged-goods stores, bar attendants also sell unopened bottles of alcoholic and nonalcoholic beverages to be taken from the premises. Taproom attendants prepare and serve glasses or pitchers of draft beer.

One of the more important aspects of a bartender's job is making sure a customer does not drive a car after consuming too much alcohol. The bar and the bartender who sold a customer drinks can be held responsible if the customer is arrested or has an accident while driving under the influence of alcohol. It is no longer just an act of kindness to limit the number of drinks someone has, or to keep someone from driving under the influence; it's the law. The bartender must constantly evaluate the customers being served in the bar. It is the responsibility of the bartender to determine when a customer has had too much alcohol.

Bartenders should also have good listening skills, as the barstool often doubles as an informal confessional. Many people become talkative after a drink or two, and a friendly ear can increase the size of a bartender's tip significantly, and turn a customer into a "regular."