Techniques on how to get yourself noticed and rescued
Build A Fire
In order to give yourself a chance to be seen by passing planes, build a fire at the highest, or most noticeable point on the island. When and if you hear or see a plane, or ship, nearby, toss damp moss or branches on the fire. This will cause the fire to produce more smoke, giving you a better chance of being seen.
Attract Overhead Planes
To get the attention of planes that may possibly fly over the island, in addition to starting a fire, you would want to arrange rocks or braches in an unnatural pattern, or spell out a word. Spelling out the letters "SOS" or the world "HELP" would tell the planes that there are people stuck on the island that need to be saved.
Get More Obvious Attention
If the arrangement of rocks, and branches, and lighting a fire fails, there is still one last hope. You can get someone's attention in the plane by reflecting light at it. Find something reflective, preferably a mirror if possible, and reflect the sunlight onto the plane. Wiggle the mirror so that it is more obvious that someone is controlling the reflection and it isn't comming from another source.