Begin with a playable brief
Decide whether the map is a real-world approximation, a transport challenge or a scenic build. List the towns, corridors, water bodies and industry relationships that support that goal before sculpting detail.
Build in layers
- Establish overall terrain and water.
- Place major town and industry regions.
- Test road, rail, port and airport access.
- Check that at least one early route is practical.
- Add vegetation, ground detail and landmarks last.
Terrain that looks convincing can still produce impossible station approaches or unusable ports. Test transportation geometry throughout the edit.
Preserve iteration points
Save named versions before large terrain or settlement changes. Keep a clean base copy and a separate playtest copy. Mods used while authoring become dependencies for anyone opening the map, so include only what the design genuinely needs.
Playtest like a player
Start with normal constraints, inspect the available industry chains and attempt an early passenger and cargo route. Check whether terrain cost, distance and access create interesting choices rather than one mandatory solution or no viable solution at all.