3. Waterproof your camera. If your camera has a housing, then buy it, the underwater life in Tahiti is amazing. If your full-size camera is too expensive to waterproof, buy a compact camera and get the waterproof housing for that.
4. Leave a day open.** Don't over-schedule yourself, leave a day open, rent a car (learn to drive manual before you go) and drive around the (one road) island. Photo ops will present themselves!
5. Learn a bit of Tahitian.** The Tahitian people are very warm and most of them know English, but they really open up when they see effort to speak to them in their own language.