The most successful small businesses have strong revenue and profit margins. Here are some of the types of small businesses that are most successful: 1. Legal services. 2. Accounting, bookkeeping, taxes, and payroll services. 3. Real estate leasing and sales. 4. Dental offices. 5. Outpatient care businesses. 6. Custom design services. 7. Warehouse and storage companies. 8. Mineral quarrying and mining. 9. Medical laboratories. 10. Secondary schools and education.