Salespeople are smart, they will figure out your compensation package to work to their advantage, so make sure that is aligned with what you want them to do. If new sales are more important than "maintaining clients" make sure the get a bonus every 5-10 new clients. Make sure they have a support system so they don't end up delivering orders instead of selling. Setup the system so if they don't sell, they quit and if they haven't sold anything new in x amount of time they don't get any commissions from "old" sales.