Sorry I didn't have time to clean this up so it's a bit of a jumble of ideas.
Think about why the map exists, who created it, why did they create it (Navigation, reference, political or religious reasons?), how did they get the information for it, what tools did they have to make it with (Did they have modern computer graphics software?), what level of knowledge of geography, cartography, navigation, etc do they have.
How do the people responsible think about the world? Do they have modern idea of "Westphalian Sovereignty" with fixed borders?
What is the extent of the map? How much of the world does it show? What shape is the world? If it's a globe, where on the globe is this?
Just thinking through all of those questions should help a great deal.
I'd strongly suggest working out all your geometry first, then only once you have that completely (or at least almost completely) nailed down should you start to think about cartography. Then the first step in cartography is to remove as much information as possible. Less is more: if you don't need to include something to accomplish the purpose of the map, don't include it because it's adding clutter that distracts from the important things. Having thought about it and integrated it with everything else will make for a better map even if it's not represented directly as features on the map. It's like the writing advise that you need to "kill your darlings".
Your geometry is "blobby" and suffers from "rectangularitis". You've drawn some broadly wiggly lines that fit neatly into your rectangular map extent. Some medieaval maps did sort of do this, although they tended to use higher frequency wiggles and a circle rather than a rectangle. They also differed from modern maps in many other ways so if you want to create a medieaval "mappa mundi" type map that's something you need to decide right up front.
The placement of what appear to be settlements also seems far too regular and the distribution of sizes of the settlements seems off, think about each city needing to have a certain number of towns around it, each town needing a certain number of villages around it, with each town needing to be within a minimum travel time of a city, and each village needing to be within a minimum travel time of a town.
You have harsh pixelated lines that do not look good at all. You also seem to be combining feature symbols that were drawn at different scales which gives them a mismatched appearance. The texture behind everything also seems to mismatch with the symbols You are also reusing symbols a lot. The way you overlap them in the forests ends up as a cluttered mess. You would need to use symbols that can "erase" the symbols behind them by having a white fill inside them.
Those gradient effects you use for the water look extremely "done on a computer" as is the bright blue colour. The way the gradient fills in from the edge of the map extent also looks very "off". The only physical medium that could even come close to that would be airbrushed paint and even they it still wouldn't look quite like that.