When wanting to expand your business there are ultimately 2 things that can be adjusted to stimulate that change. One is your service or product, the other is your target audience. All shifts in what market segments you capture must come from an adjustment to one or both of them.
For example: Lets say a garage does the majority of their business through selling and installing tires. Their current clientele is made mostly of neighborhood people buying average tires for average cars. They want to grow their business by attracting more tire buyers. They basically have two options:
1. Change the Audience - Advertise heavily outside of their normal geographic area to attract drivers from other areas. They would likely have to provide an incentive to convince those drivers or have very effective advertising to be successful with this.
2. Change the Product or Service - Start stocking specialty tires of some sort. An example could be high performance tires. This would attract the auto enthusiasts that normally wouldn't have come there looking for tires.
This is a very simple example, but the point is clear. If you want to attract a segment of the market that you have not attracted yet, you must make a change to get their attention. In the end, those changes will be either to the service or product you offer, or who you offer it to. Evaluate both, compare possible changes to what your strengths are and what the competition offers. Then do it!