Choose "impossible" goals
When faced with a hard-to-reach goal, your best strategy may be to shoot even higher. Like aiming a punch or a kick "beyond" the target, aiming impossibly high will at least get you where you need to be, and will quite likely create a vacuum-like momentum that will pull you far beyond what you thought possible.
One of the reasons that this works is that by setting such high goals, you instinctively understand that what has worked before isn't going to work now - which ensures that "the way we've always done things" will be the first item on the chopping block. For example, if no one has ever made more than 30 sales in a month in your showroom, and if you determine that you're going to shoot for 50, it's quite obvious that the thinking and behavior that is normally employed to pursue sales simply isn't going to cut it. You'll have to sit down and figure out what sorts of things a person with 50 sales would have to have done to get them. Harebrained and even absurd possibilities that pop up in such brainstorming sessions suddenly become reasonable achievement strategies. Perhaps the thought comes that maybe there's a better source of clientele than walk-ins - instead of just waiting for customers to come in, maybe you could host a series of classes showing how to get the best out of your product. Or perhaps you might start having sales lunches with old or repeat customers to pick their brains for ways to enhance your sales package. Or maybe researching mass-purchase possibilities by corporate-level buyers is a better option than focusing on the single-purchase buyers that normally generate your commission check.
Of course, despite all your creativity, it might not work. You may never hit 50 sales. But, at the very least, with your new strategies, high-level targeting and newly generated enthusiasm, you're more or less guaranteed to hit the previous ceiling of 30 sales without batting an eye.