No partnerships can last long-term if one partner is dishonest. Willingness to work hard. Though no two people work alike, each partner must be committed to the cause. You should define job responsibilities before you begin. Each partner must bring useful expertise to the business.
Money can start a business, but ability keeps it going.
A good team player. A partnership, regardless of the number of partners, is a team sport. Partners must work independently when necessary, together when beneficial. Good people skills. Good partners get along well with all types of people.