I'm looking for the same answer, but I'll share what I found out so far (the hard way). There are two ways to pay a salesperson. First is by comission, where you pay according to the amount sold. This is best, but it will be hard to find somebody on this terms if you're a young startup. Second is where you negociate a salary, and you set a target. The target need not be about sales, it can be about appointments set (very useful), calls made, emails sent or any other metric.
Now, the don't-be-stupid part: never _ever_ hire somebody in sales with fixed salary without targets. Where there is a salary, there must be targets. You can of course offer both comission and a salary, but the salary must be dependent on some other metric then the comission.
Also a good part of the sales process is finding the best metrics. It should be something like: for 100 phones you get 5 appointments, from which you get 2 second appointments and 0.7 contracts. Each of those steps can and should be optimized separately, once you have the process established.
Now, the don't-be-stupid part: never _ever_ hire somebody in sales with fixed salary without targets. Where there is a salary, there must be targets. You can of course offer both comission and a salary, but the salary must be dependent on some other metric then the comission.
Also a good part of the sales process is finding the best metrics. It should be something like: for 100 phones you get 5 appointments, from which you get 2 second appointments and 0.7 contracts. Each of those steps can and should be optimized separately, once you have the process established.