As more and more people earn their CFP certification and become financial planners, the mere fact that one is a financial planner is no longer the differentiator that it once was. In turn, financial planners find themselves increasingly compelled to focus into a niche where it's easier to stand out and win clients... being a generalist may bring a lot of prospects but few clients, while settling into a niche may narrow the field of prospects but results in an incredibly high likelihood that clients (in the niche) will say yes and choose to do business.
Of course, a niche is not just conceived overnight; in practice, it's established and refined over time. It starts with a target clientele, which leads to developing a unique expertise for working with those clients and the problems they face, and that in turn leads to the development of services and a business model to fit the clients and their needs. As services are delivered, new ways to focus on the clientele emerge, new expertise is acquired, the business model is further refined, and the process continues to iterate until a finely honed niche emerges.
However, that still leaves open the key question: how do you find or choose a niche in the first place? In truth, there are many paths to finding a niche, from focusing on a passion, to an area where you already have an affinity or connections, to your existing clients or even former colleagues in a prior line of business. For those who truly have "no idea" what to do, the easiest path may simply be to start taking anyone you know out to lunch, asking them what their needs and issues are, and beginning to define a vision for your business accordingly. By asking people what's important to them and unique about their concerns, you can find a niche of your own, and may even discover that your interviewees become the first people to refer clients to your new business.