I thought that the first thing to do was to find the gramophone and eight records ;-)
I'm assuming that your island has big hills, high cliffs or very tall trees if you expect to be seen by ships up to 30 miles away. If you're standing on the beach the distance to the horizon is roughly 3 miles, not 30.
Even then it would probably need to be quite a big fire to be spotted during the day from a distance of 3 miles, although even a small fire could be picked out on a clear night from that distance.
Personally, the first thing that I'd do would be to seek a source of (non-saline) water. Without it my survival time would be extremely limited. I'd rather be found alive after a long time than dead after a short one.
Chris