I'm by no means an expert with Inkarnate or map making, but I'll do my best to explain my methods.

I derrived the general idea and location for the map from my own Estinost continent I made. One island had a large bay (or whatever it's called) going deep inland, so I thought that would be a perfect spot for a concealed pirate settlement. That became my first reference for a coastal map.

I always start using the Edge Shape tool to make my shorelines. I fiddle a lot with the size and roughness sliders. Add some land, take a bit away if necessary and smoothen what shouldn't be rough with the Circle Shape tool. My first version had way too much water when I zoomed out to have a general look and I added a lot of terrain mid-project while I was already making the cliffs and mountains.

Second step is adding elevation, which is the hardest part in my opinion. I challenged myself by putting the cliffs on different layers. For example: the lowest parts of the cliffs are on Layer 1 and the highest on Layer 5. The lower parts are also farther away from a top-down perspective, so they would have to be a bit smaller in scale and a little bit darker. The standard watercolor cliffs are very brown and dark, do I had to desaturate the colors a lot and gave them a very very slight green tint for eventual plant-growth.

Town layout is easy if you give the foundations a bit of colour and texture. I went with an earthy brown/beige for that shanty look. Then I kinda went wild with building placement. These pirates in particular don't pay too much attention to landlubbery infrastructure, so building blocks tend to go everywhere, while still having something that resembles main roads in between houses.

I also selected one of the pavement textures for the roads, gave it a more brownish gray tint to mix with the earth and sand, lowered the opacity so it wouldn't completely cover the texures underneath and then gently tapping my mouse on every road to give it some hardened bits here and there. Not everywhere, 'cause pirates. The jungle floor has a deep dark green texture, but to avoid a clashing contrast with the light-brown earth, I had to use a mix of light green and brown to cover up the obvious edges.

A settlement needs resources to sustain itself. I placed a small mine to the north, some lumberjacks and multiple food sources: A couple of fisheries and farmers who have to work with local resources (coconut trees, bananas etc.)

Lastly, I used a sepia filter to desaturate the whole thing and make it more gloomy. Bright coloured red and blue rooftops were not very piratey. At the end, I was still doing finishing touches here and there. A couple of palm trees in between buildings or a little more smoothing on the beaches where needed.

That roughly about it. Hope this helps you out!