First things first: do some market research because the more you know about the holes in the market, potential customer base and your competition, the easier it will be for you to identify your niche in this new market. You should also listen to your customers. Is there something they think is missing from your product/service line? Last but not least, be sure to follow these steps once you have your new product ready:
Step 1: Define your new target market or markets
Step 2: Do your market research
Step 3: Enter the market or look for another target market
Step 4: Create a plan to enter the market