Airport vendors are overpriced, waste your time and often try to trick you into attending timeshare presentations. Skip this bullshit and enjoy your vacation!
Whenever possibly use your credit card to pay for restaurants, tours, and nightclubs. Visa and Mastercard provide excellent realtime exchange rates!
If you go out be mindful of your valuables. Mobile phones hanging out of your back pocket might not be the best idea, unless you really need a new phone.