The most important factor to consider when starting to build a business is the target audience. You have to think of who would you want to cater to. Who are the communities that you may profit off of. Like for example if there is a school near you, you should know that students would be your target audience. You should start a business where students can buy materials from or a place they can study or even hang out around. I believe that if you studied your target audience, the first step of your business is already successful enough.
Yeah, I always think first the target audience before starting a business because your branding will depend on your audience. You don't want to act as a luxurious brand, but your target audience are just average people. The whole branding and pricing will always depend on the target audience so it's better to know them first before starting everything. I agree with you that this is one of the first steps in business, you don't want to do everything blindly because you won't have a path. Knowing your target market saves you from mismatched branding and saves you from mistakes and it's your guide for your marketing style.