So, start with your blank canvas which is three walls, a window, a ceiling and a floor. Get these looking good first and you won't need to lay out cash on things that just serve the purpose of covering them up. There are a lot of choices here we can cover later. Then think about how you are going to work, Are you going to do make up in the shop area or in a room out back. How much work area do you need, what sort of surfaces and what size. Think about all the materials that need to be close to you. Think about all the rubbish that you don't want people to see. Where you locate the checkout/till can be critical. Put it by the door and a lot of people won't ever see what's at the back of your shop. (I'm guilty of this one!) It's also a security risk as it's so easy to just walk through the door and open your till. (I've sort of covered this by having an extra deep counter)