Build a karve, and sail till you find low level landmasses. You'll be able to identify them easier the more experience you have so it may be confusing now. But look for those type of silhouettes in the 2nd large ring of the map - you may have to visualise it being large doughnut with the centre island being the dot on the map. Once you do spot such a land mass, you can scout it by just sailing near the outside of it, look for green lights, there's two main sources of it, but one usually means it's an important point of interest. Also, make sure to look for deep swamp biomes. Narrow ones that border the outside of an island usually aren't that resourceful. You don't want a Chile-shaped swamp biome, you want a good thick Brazil-shaped swamp biome. Means more POIs can spawn.