Marv Gandall gave the following definition of petty bourgeois:
Small merchants, manufacturers, farmers, and other urban and rural propertyholders in local markets whose income derives mainly from profits, rent, and interest. Theis distinguishes them from wage- or salary-earners who sell their labour power to others.
The above groups conform to the classical definition, i.e. small property owners. I would also include doctors and lawyers in private practice. Perhaps more controversially, I would include people like professors, journalists and skilled workers at the high end of IT. True, such people do have to sell their labor power, but have sufficient income, social status and control over their conditions of employment to make them more individualist than collectivist in their habits and lifestyles, i.e. more like petty bourgeois than proletarians. Of course, the "new petty bourgeois" groups I have named tend to be urban-cosmopolitan, and thus more likely to have voted for Clinton than, say, Midwestern used car dealers and grocery store owners, who probably leaned toward Trump. There are petty bourgeois and petty bourgeois, in other words.