Tips and recommendations for luggage (some self-evident, others maybe not):

"Tourist card"! (Embassy, travel agency)
mosquito protection,
Shorts, t-shirts with and without sleeves, bathing suits,
Acute / continually needed drugs
sunscreen cream,
Ohropax or similar. (Concerts / night rest)
Credit card (s) (to draw cash at the machine) with PIN, best VISA
EUR cash (some)
Copy and saved copy (Internet) of the passport,
International driving license if applicable
good mood,
Openness, interest for country and people, patience,
At least 1-x adapter plug (on American standard, 110 Volt)
Camera + 1 spare memory card
USB stick
dictionary
Travel Guide

What not
US Dollars (could change now)
EC card (does not harm, but does not use)
Western arrogance