Though most entrepreneurs start out alone, new businesses increasingly start as partnerships, according to business writer Bruce Barringer. Good partners share the workload, the risk, have complementary skills, and provide considered second opinions. The sources for business partners are myriad and depend significantly on your previous experience.
You may have to explore far outside your bubble, but if the business idea is good, then the right business partner is out there.
If you're starting a business in a field where you have little experience, you're probably going to have to do a ideas and a solid business plan to bring to the table, and your confidence in these ideas is going to help you get through.
Start making contacts at trade shows, local business association meetings, and professional associations, depending on the type of field you're looking to enter. Make sure you can concisely break down what your business and don't be shy about asking people for connections.
Consider also looking at volunteer and non-profit work to build up your resume and network. A wide range of energetic, confident people work at these organizations who might know important people or have the makings of good potential partners themselves. Coming into contact with a broad cross-section of people will also help you work out kinks in your business plans. Pitch your ideas to willing listeners, and take constructive criticism, but ignore simple naysayers.
If you've had good relationships with bosses and other experienced business leaders in the past, consider them as potential partners, and indeed ask them for advice. It can be awkward to work with a former boss in an equal partnership, but the additional experience they bring is often invaluable. If former mentors suggest a partner, be sure to get to know them well before jumping in. Just because someone you trust recommended them, it does not necessarily say they are the right fit. Maybe they worked well with someone you trust, but it does not mean they'll work well with you.
Consider former co-workers as well. Their abilities should be easier to judge, and you'll already know if you work well together, whether they share your vision, and whether you can trust them. However, avoid co-workers that are too similar in skills and experience. Consider people you know well, but who worked in separate teams or departments.