Here's my first little islet for the Sea of Os'r project. It's called the Isle of Oxuders [PDF]:
At high tide, the Isle of the Oxuders appears to be two tiny islands.
The megalith is visible from a considerable distance to anyone keeping active watch. However, from the sea, it may be mistaken for a natural rock formation. The islands’s other points of interest are not evident unless the party makes a landing.There is a 2 in 6 chance the cast-away will spot the PC’s vessel, and ignite a signal fire on the highest point of the island, which otherwise appears uninhabited.
Boats landing on the beach at low tide must contend with oxuders, who often surprise by launching themselves from concealed burrows in the sand.




Players start the campaign knowing the relative distance and direction of some interesting destinations, but they'll have to explore and make their own maps. Such a framework allows the world to grow organically. Another option would be to give the players a world map which you stipulate is inaccurate in many particulars, because of the difficulties in a world where most people rarely travel between the "points of light" in a vast wilderness.