There is excellent advice in the previous answers to this question. A couple of cautionary points:
1. In my experience, sales teams follow a similar make-up of a few star salespeople who are knocking it out of the park, a large middle segment who are meeting quotas but aren't achieving superstar status (some want to, others don't - it's good to figure out who's who in this category), and a small segment that is struggling just to make quota. The superstars will perform well regardless and will likely obtain all incentive rewards you put in their path. If your incentive plan targets the middle range segment to start, the results will be a good indication of how well the plan is working. And you can adjust it as you go to accommodate the superstars and strugglers.
2. Picking up from point 1, don't make the incentives so hard to obtain or achieve that they become a disincentive. I have seen business owners do this under the erroneous assumption it will motivate people to reach higher, but all is does is demotivate and demoralize your sales people. Whatever incentives you offer, make them achievable while also requiring your "middle segment" sales people to go outside of their comfort zone. Best of luck! I'm happy to discuss further with you.