Target audience should always be in the pit of your mind before you opt to create a new website design (or have one created for you), and by considering their needs, you’re more likely to generate increased sales.
You have to think about your target audience in quite strange ways. Think about who they are, what types of things they get up to, the music do they like, how old are they and so on. Of course generalising a group of people is difficult, and not each of those individuals will be who you think they are.
So long as you have a good idea of who your target audience is, even if it based on estimations, it should show in your website design. Finally, if your website is to their liking, they’re ultimately going to stay there longer, and it essentially gives you greater chance of converting them into a customer.