The historic centre is walkable, and that is the best way to see it. Keep valuables discreet in crowded market streets and avoid wandering aimlessly after dark, especially around empty port roads.
For beaches and sights outside the city, use buses, taxis, or a rental car. Pointe-à-Pitre itself is a hub; it is not the easiest place to drive casually, and parking can be irritating in the centre.