This is a dilemma every new entrepreneur faces. He or she has built a product that is relatively unknown even though it may be good. Entrepreneurship venture is often a one or two person adventure. It is hard to gather the resources that are needed to make the product popular on a massive scale. A poorly marketed product may not be successful.
The best strategy in this case is to go small and cover less bases at a time. Sure , it is a tempting thing to just go out and try to win a large market share ( for example by splurging on ads) but it is important to first ask, can one handle the demand that market will place on the product and entrepreneur's team. Often the initial success leads to euphoria that the product is doing extremely well and the entrepreneur is tempted to expand his territory. The reason for a new product doing well may be pent up demand which was till now unfulfilled. The entrepreneur may thus read the demand completely wrong.
Developing a strategy for future
One way to have sustainable demand is to listen to what your current customer base ( or to be customer base) is telling you. The next is to implement them. That means working on the demands is priority and devising solutions that help the customer in solving their problem. In other words to create a product that caters exclusively to the demands of your customers.
Soon the entrepreneur will notice a market that is ready to buy his product. It may be a very small segment of the overall market but if the product caters to more than 60-70% of that segment, it can be considered doing extremely good. It does not matter if the overall market for the same kind of product is much larger. The important part is if the segment that entrepreneur is operating in, is profitable enough to survive. The entrepreneur may not have the muscle to win the market share from the competitor but at least he has cornered a significant portion of the submarket.
The discovery of such a segment is not easy and it is not possible to accurately pinpoint such a segment even if market research is carried out. Yes one can get a good idea of what sells but then even observing what people buy can give a fair idea of what works.
The best strategy according to me then is to
create something which is similar to what a popular product is about
Adding a few elements that are not there in the popular product
Market it in a unique style
Find out early adopters and ask them to try out your product
Make your initial customers as brand ambassadors and ask them to talk about your product
By creating some sort of exclusivity for your product and segment, you can attract a significant portion of untapped market. You know your business best and the things that work over there.