<human>:  What is the best way to plan a 21st birthday party?
<bot>: The best way to plan a 21st birthday party is to start by deciding on a theme or atmosphere of the event. Once the theme has been chosen, decide on a venue, date and time, create invitations, pick decorations, prepare food and drinks, and plan activities or entertainment. Consider the guest list and how large the party will be when making all of the planning decisions. Finally, consider the budget available and prioritize the most important elements.