There are assessment tools that help when recruiting for sales roles. These are great for ensuring you get the right people with the right characteristics. Here are a few useful tips for recruiting without assessment tools.
A good salesperson must be motivated by financial rewards and should have a desire to take risks. The salesperson must be confident, with good verbal and written skills.
They must have good presentation skills as well as good negotiating skills. Usually, sales people are extroverts. There are however some introverts who sell very well, although they are few.
Lastly, they must be able to get over customer rejection and be proactive in seeking business. You can check all this at the interview using competency based interview questions, work sample tests (here you give them one of your product to sell at the interview, this gives great insights) and also by checking their references from previous work.