"Dusseldorf is named after a wealthy german town in real life" - yes I know; I live closly to Düsseldorf. Because of the namings I tought you would be German; but now I am sure you're not so; the Bundesland (simliar to an US state) of Nordrhein-Westfalen, where I live in and Düsseldorf is capital of. Inside the Rheinland we have an own carinval tradition. One part of the carnival tradition is the hostility from almost all other Parts of Rheinland against Düsseldorf. As someone from the Köln (Colonge) area I have not a good oppion about Düsseldorf. That's just the background.

For the naming; on my RP-world I have a larger mostly Germaniced Region names Nordera. Unlike much other areals of the RP world the cities, castle and abbey are not named by historical or real places like in the Roman or Egyptian area.

For Nordera almost all names are combinded by two word. The first one mostly a name, an animal, a colour, something geographical, a produkt or a description of the areal. The second one is a namefore of what it is or about the areal. The names itself are german, icelandian, norge, danish, english oder dutch. Sometimes I change a few letters with historical similars.

Here a few Examples:

Dökkhain - Dökk (icelandian - dark) + hain (a german word for a forest) | Dökkhain ist the name of a forest and town inside the forest.

Föxbug - Föx (Fox but with an 'ö' - sometimes you can do it that way ;) ) + bug (norge: bukt - bay | kt is similar to g) | Föxbug is small but rich town. It holds a harbour and is a merchant centre. Beside that there are lots of foxes around the town.
Wassenstejn - Wasser (german for water) + stein (stone - but maybe here better to translate with hill. In old german and latin 'j' and 'i' were used similar)
Mörrford - Mörr is an old and rare family name. Ford is ford (in german it would be a furt like seen in real Frankfurt - frankish ford)

I hope you understand my system. It is also not so far from how real germanistic city/town names are created. Most times the real names of cities and towns are a mix of two or more words or a blurred latin name - but the latin way is much harder; best seen in Köln (Cöln, Colgone, Colognie, Colonia, Colonia Aggripina), Aachen (originated from Aquis Grannum), Neuss (Novaesium), Mainz (Mogonatium), Trier (Augsta Treverorum), London (Londonium), Colchester (Camulodunum), and much more. For this way I cannot give you a good best practice way.