Near where residents live there need to be transportation, schools (elementary (one of schoolhouse, small, big, or museum) and a high school), parks, fire, police, sports, church or mosque buildings, and health facilities. The more of these that are closeby, the more likely rich inhabitants will move in.
Once you can build a big city hall, start zoning dense residential, commercial, and industrial so that more rich people can live and work in your town.
