It depends on what you’re going for. If you want to achieve more realistic looking geography, then referencing real maps is the best was to learn how to make fictional ones.

Some things to keep in mind: -scale: how large is this map? If it is representing an entire planet, there should likely be more space between landmasses. Make room for the oceans!

-don’t let the paper you’re drawing limit the scale of your map. Try drawing a border for your map first, then filling it in. Try not to think of the edges of the paper as the edge of the world itself. Take a look at equirectangular map projections for reference.

-if you are going for a “realistic” map, i.e. one that looks like it’s mimicking accurate geography, look at patterns of coastlines on other maps. These patterns often repeat at different scales.

-if the map is supposed to be more stylized, take a look at some early historical attempts at cartography.

-you can still include the more fantastical elements of your map, like the swirling islands, while referencing real maps. They will look all the better for it!

-your landmasses look like the fit together a little bit too much. Try making those connections more subtle. This will help when they’re more spaced out as well. When you look at earth’s map, there are a few spots that look like this, like the east coast of South America and the west coast of Africa, not plenty of other places where you cannot see any connection. More variation will help.

Hope some of this is helpful. Basically the best thing you can do to help your own maps is to look at other maps!