The (north) west piece of my campaign world called "Anthemios". I plan to use this style of map for the entire world, but I'm looking for advice on how to create the city maps, my current process for making cities is terrible.
That's a delightful painterly style. About the only thing that looks awry is that some of the rivers are TOO obviously just drawn across pre-painted terrain. The strongest impression of this is that spot in the northern mountains where the river's path seems to run over the edge of a mountain. All in all, though, very nicely done!
I don't know about workflow you might like better for city generation, but as a general thought, to stay compatible, maybe a compatible style would be looser painted suggestion rather than detailed precision. Or maybe if you need SOME degree of detail, using intentionally sketchy / handdrawn linework would work. You do realize, that in order to suggest better city methods, you're going to have to show us the present methods you don't like? Don't fret - with an intro like the NW Anthemios map, we won't think poorly of your cartography.
Agreed. That's a very nice painted-feel map. As for towns and cities, either a daub of paint (maybe in red, or yellow for contrast) or a rough inky sketch that looks as if it has been added after the rest of the map has dried might work? The first would be relatively easy and would keep in theme but might not be the look you want. The second would be harder to achieve, but might be worth the effort. Maybe consider doing the towns in an oxblood or sepia colour. As long as they don't fade into the background too much that might work nicely. Just some thoughts.