Start with three places
Note where you arrive, your main destination and where you will spend the evening. A good address reduces travel between them; for a short stay this may matter more than another star.
Centre or a specific district?
Centre is a broad term. Check the street and building number. Śródmieście, Wola and the airport area serve different plans; assess transport for the actual address.
Plan the return journey
Check the route after your event as well as during the day. Account for luggage, weather and everyone travelling with you.