Stay in casa particulars (no hotels or resorts). Take a lot of euros or dollars with you. You can exchange the for pesos on the street for a much higher rate than at the bank. Save some of those euros/dollars for long taxi rides. Absolutely use express VPN if you intend to book buses using their viazul website. You won’t be able to pay for your bus otherwise. First thing you do when you get there is try to acquire a sim card. I would advise doing it officially and not picking one up of a street vendor as 50% of the time you’ll find the SIM gets cancelled.

Visit baracoa, viñales, Santa Clara, Santiago de Cuba, Trinidad, and Havana (both old Havana and the suburbs).

Drink a canchanchera. Go to all the local music halls you can. Drink a michelada. Smoke their cigarettes (Jesus they are good). Eat the seafood in baracoa. Dance. Try not to get too caught up in tourist traps. Talk to locals (learn more Spanish than I did). Have fun.