Why not expect more sales success than you're used to? As marketplace pressures and product commoditization increases, can you afford not to?
Enabling your salespeople to withstand - and deliver on - higher expectations is expensive - in dollar- and change- costs. You'll have to rethink your sales approach. Put more time than you're used to into training. Get to know your buyers and your salespeople with as much subtlety as you know your spouse. You might prefer your usual success rate to making that kind of commitment.
If not, here are some tactics. Don't take my word on their effectiveness.