There should be no evidence of any work on the premises that the neighbors can smell. For example, an offensive odor, chemical fumes which permeate the air, or a carpentry business that raises a lot of dust would probably be prohibited in most residential areas. Any increase in car, truck, or pedestrian traffic may be illegal. Vehicle traffic usually violates restrictions on noise and odor. Taking up limited parking spaces can prompt complaints from neighbors.
Many cities prohibit signage altogether.
Neon or lighted signs are out of the question in most areas. Contributing to this constraint is the fact that many zoning laws prohibit any kind of business that involves inventory. These vary widely depending on your city. For instance, some communities have an additional charge for running a consulting business at home. Others limit the number of commercial phone lines a residence can have, or require that commercial cooking and baking be done in commercial kitchens.