Attorneys can assist you so that you attend the interview and are fully prepared at the interview. Attorneys can also assist with procedure, making sure the case is on track. The law does not require you to have an attorney, but many people feel it is useful. If you go to the interview with even a single item of evidence missing you will cause a delay. If you can live with that kind of delay, no big deal.
Teachers are a good example.
The bottom line is you will need to convince the consulate that you can afford to live in the US with the legal salary you will be earning. Of course, those employers will have to file petitions for you, but many part-time jobs can add up to more than enough time and money. I wanted to start a partnership business in the state of California. There is nothing preventing a foreigner from investing in a US business. That being said, you will not be able to work for that company unless you obtain work permission.