How do people overcome cravings for alcohol?

Many strategies. In addition to dr. Blixt's fine suggestions, avoiding sugar & taking high doses of vitamins b1, b3 and B6 can be very helpful. Those who crave alcohol usually have hereditary metabolic imbalances & often are also addicted to sugar, caffeine & tobacco. They are often depressed. It is important to address these issues as well. The vitamin cure for alcoholism by abram hoffer md is a great resource.
Taking with others. One best way to overcome cravings is to talk about them with someone else who cares or who has had the same struggles such as people in the rooms of aa. Medications can be helpful as well but only if used with other support. Getting around healthy people and finding other ways to fill the void left by alcohol, eating healthy, exercise, they all help. You dont have to do it alone.