DO try the local food, ask questions about the traditions, greet before asking any questions, respect the environment, be patient when going to any administrations(people in Guadeloupe are very laid-back, we must have a no-stress policy somewhere...) , wake up early to do sightseeing if you don't have you own transport as the last buses are around 6pm only!(make sure you check the time with the driver), visit Grande-terre(with the best beaches, best nightlife, best markets...) and Basse-terre(with the beautiful rivers,natural parcs, la Soufriere volcano...) are there's a completely different scenery and temperature. the DO's list isn't abviously exhaustive but Do have a smashing time!
DON'T throw away anything on the floor always use the bins provided, don't take pictures of locals without asking them permission, don't smoke in public areas, don't take any plants from any natural parks as they are all protected, the don't list isn't exhaustive but sometimes the best way is just to use our common sense and think on how we want people to treat us and our country.
And if you unsure about something it's always better to ask. In Guadeloupe, we are very proud of our island and will be very helpful and friendly to newcomers.
So, enjoy your trip or new life in Guadeloupe!for more infos check out my group on facebook "work live and play in Guadeloupe