Hi Michael, welcome to the guild.
Scale is definitely something that can be difficult to get right and something that I've been focusing on a lot in my more recent maps. I'm not sure if you're working on a region map or a town / city map but I'll cover both as the advice is a bit different for each.
One resource I have found very helpful for both types of maps is Medieval demographics made easy (
https://gamingballistic.com/wp-conte...ade-Easy-1.pdf). I was introduced to it a while ago by another guild member.
For town and city maps, I think this is the harder type of the two to get the scale right for. You can look at that document that I linked to find size and number of houses a city should have for a given population; the document also talks a bit about how to size the buildings. Looking at surviving Medieval walled cities on google earth is also quite helpful, one of the largest surviving examples is the city of Carcassone in France (
https://www.google.com/maps/place/11...51!4d2.3517703).
Larger region maps are often a bit easier as, depending on the style you've chosen, the elements (mountains, towns, etc) are often stylised so the relative scale is not so critical. The document I linked does include a section to calculate the size of the population that could be supported by a certain sized area of farmable land and also give calculations to determine the number of cities, towns, and villages that would be included. For determining the size of terrain features such as hills and mountains I generally just pull up google maps and use the measure distance tool to look at the footprint of some appropriate real-world examples.
I hope this helps.