This is Alba's map. I'd say it's around two-thirds of the way completed, but that seems right for now. I have a hunch Alba will learn more about the map tomorrow, and the rest will become evident as she journeys.
I started out with two A4 sheets of heavy watercolour paper, because that's all I had that was suitable. You don't really want to use flimsy paper when drawing maps, as it might tear when adding colour or erasing things. I taped the sheets together to create a larger canvas. I may take the map apart again, when I decide how to fold and transport it (for Alba). The first thing I did after that was singe the edges of the paper all round. I did it first to prevent burning away some of the work I intended to do. That said, it might have been equally interesting and possibly more mysteriousd to do precisely that.
Then I drew the outlines of country and islands and sounds. I like islands, so I alway include some. My islands are almost always to the north.
The next step was to mark in the major geographical features like mountain ranges, rivers and lakes. I like to draw topographical mountains. I'm sure there are some geographic impossibilities on my map, but this is about fantasy rather than perfection. Then came the colouring fun. I used watercolour pencils and watercolour crayons.
That done, I sat down to mark and name locations. This part of the process is fascinating, because events tend to pop into my mind as I name places and landscape features. The story begins to tell itself to me.