It is difficult to know what product or service will sell in the marketplace. Given the significant amount of time to create a product or setup a service it can be more practical to try to sell first. Running ads online and creating a simple website using wordpress can allow you to test the level of demand in the marketplace. If you are unable to sell your straw man product or service there is a good chance when you put the real thing together you wont either. In other cases, if the customer is willing to wait, you can make the sale and go buy the product/service elsewhere at a lower price. Eliminating any risk.
Instead of diving into the marketplace