If you agree with the concept that we cannot do everything to everyone (because it’s a formula to be mediocre), you will need to understand your customer personas.
It’s the same concept as knowing your target market, except with customer personas, you make them like real life customers. You create personas and describe them as a (group) of person. For example, your product may target a group of young, working moms. You could name this group “Young Sarah”. Then, you come up with her descriptions. For example, the young Sarah has a busy husband who travel all the time. She works full time and also has to look after a one year old boy. They are a double income family. When you have her profile in mind like this, your campaigns and your messages will be specific for her. You are talking to her.
This concept is critically necessary for your marketing efforts. Unless you have unlimited resources, you will need to be clear on who your customers are.