Alcohol-related gifts may be a welcomed part of a 21st birthday gift basket, depending on the recipient. Include a monogrammed shot glass or a painted wine glass along with small bottles of liquor and a cocktail shaker. Alternatively, pick out things that the person can really use at the beginning of adulthood; a book of simple recipes, a small set of tools, decorative items to use in an apartment and gift cards are all thoughtful additions to a gift basket.
If the recipient intends to drink alcohol, pick up a variety of miniature bottles of different kinds of liquor, or fill the basket with common mixers such as triple sec, bitters and tonic water. A small book of cocktail recipes is a sweet touch for an inexperienced drinker.
In addition to alcohol, or in place of boozy gifts, fill the basket with small items in amounts of 21. For instance, pick up 21 of the recipient's favorite candy bars, or gather 21 quarters; they're handy on laundry day. Write down 21 compliments or pieces of wisdom and tuck them into the basket too.
Gift cards for gas stations, movie theaters, grocery stores and restaurants are sure to be appreciated by a young adult.