It's going to be hard to think of a strategy that will help you win the game esp. when all castaways are living in one island.
I think the best strategy is staying out of trouble and being quiet most of the time. Get to know the players individually and find something that you have in common with each on of them. Don't talk strategy at the very beginning though but do be aware of alliances forming and get involved. Don't promise people at the beginning. And also be involved in the camp, make fire, catch fish etc. Play strong in challenges a little bit but not too much until probably the end so that you don't pose as a threat too early. Be nice eventhough you might hate their guts. Win at the end.
