Before you set sail, spend a great deal of time doing as much research as possible about the history and culture of Cuba. There is so much you will learn while visiting Havana so having some context before you go will enrich your experience. Also, read as much as you can about traveling in Cuba i.e. currency, food, water, shopping, customs/etiquette, and how to make the most of your time in port. The presentations/lectures about Cuba on the ship are very limited and not very comprehensive. Watch documentaries and movies set in Cuba because the ship programming does include this kind of educational opportunities. Do research about eating in Cuba to taste the local cuisine because the menus and culinary themes on the ship do not consistently focus on Cuban food. The Ernest Hemmingway historic sites are really worth visiting. The historic walking tours are excellent. The local shops are great and the huge craft/flea market is wonderful. Photo opportunities are abundant. Politely ignore local folks trying to sell you a cab ride, cigar, or sketch of yourself and they quickly vanish. People are very friendly, the city is extremely clean, the public gardens and squares are beautifully maintained, the architectural detail is extraordinary.