From your arrival at the airport I suggest going to Gustavia, walking and (window) shopping, and gaping at the mega-yachts (the tourist board office is there and they have a great One-Day in Gustavia brochure). Have a cold drink or coffee, walk around the whole marina to the other side, and visit "St. Barth Stock Exchange"-- great off-price shopping. Go to Do Brazil at Shell Beach and have a snack or swim. Then head over to St. Jean for people watching or go to the beach there (you can rent chairs next to La Plage (Tom Beach Hotel). If you really feel like motoring, you can drive around the whole island in less than an hour. If you do that you might like to see Saline beach.Let me know if you want any more info.