Early sailors had limited navigation skills. Pirates mainly found other ships by waiting on known trade routes.
To know where they are, sailors use latitude (north and south distance), and longitude (east and west). They could estimate their latitude from the position of the sun in the sky, but longitude was more difficult.
The magnetised needle of a compass always points north so pirates used it to work out their location. Pirates would work out their longitude by seeing which direction was north and then guessing how far they had travelled east or west.
Pirates made compasses at sea by stroking a needle against a naturally magnetic rock called a lodestone.
Having a compass helped, but the most useful of all was a sea chart. Spanish ships had charted much of the “New World” coast early in the 16th century. With a chart it was easy to plunder the wealth of new coastline areas. Pirates called books of charts “waggoners.”
Telescopes were also very useful. Even if pirates could not see land, they could still judge their direction and distance by looking at the clouds and sea birds.