Marketing as a first step would be a crass mistake. What could you possibly market if there were not strategic or action plans in place from which goals could be established?
The first step in any new business is to be able to define the purpose, mission and goal of the business, all in one sentence. If you are able to answer what you are, what you are in the market for, and what you are going to solve, achieve, or change in the market, you should already have a primitive idea of what will become your brand.
According to Chron.com, a year before you even start there should be plenty of research conducted on how your good or service is currently performing in the market. Who is buying? Who stopped buying? What is the shelf life of the product? Who are the key competitors? All of this leads to the writing of a full business plan. This would also include the budget needed so that any business loans, or lines of credit, are secured.
Nine months into the start-up, the business owner should get all needed permits and licenses. This also includes looking into any potential copyright infringements, trademark issues, and other legal things. Notice that none of this includes marketing yet. It would be very dangerous to start marketing and offering a product that has not been fully researched.
The article in Chron also states that, six months from startup, you should have filed either your articles of organization, or your articles of incorporation. This is specifically needed when you operate as a limited liability corporation, or an LLC. Also, in case you will be employing people to work for you, apply for an employer number through IRS. It is very important to do this.
Finally, three months before the startup, you can start looking into the aesthetics of things, such as the name of the business, marketing materials, webpages, and other different forms of marketing. This is, therefore, the last thing to consider in a business venture, and not the first.