The most important is to find a good map theme. The one I’m using now is Owl’s Los Angeles, it has this kind of arid Californian GTA V vibe. Surface Painter allows you to paint the ground with some of the basic ground types (pavement, ruined, gravel and field). It’s extremely hard to get nice looking edges though so it works best for areas that are surrounded by roads (such as inside the city center) or where there are trees or props masking the edges. Finally, Extra Landscaping Tools allow you to paint natural resources (oil, minerals, fertile land). As opposed to surface painter, these areas do have soft edges so they blend nicely. On the minus side, it only works for relatively large areas, so don’t expect to be able to have oil texture in one backyard and mineral texture in next door’s backyard.