1. Set Yourself Up On Social Media
You'll need a Facebook Page and a Twitter Page. You may want to have other social media accounts but I would recommend starting small. You're going to have to manage them yourself so you don't want to give yourself too much to do in the beginning.
2. Write A Book
You can't be an author without a book, so get writing. Prioritise it. I recommend writing the book at least twice.
3. Get A Website
I'd recommend a website with a blog. You need somewhere to send your audience when they want to know more about you. You'll need an about page, a blog, and at least one page about your books.
4. Set Up A Mailing List
You need to increase your reach with a mailing list. You can send out weekly newsletters to the people on your list. You'll want to promote your list on your Facebook Page, Twitter Page and Your website. I'd recommend promoting it on ever page of your website.
5. Edit Your Book
Self Editing is a really important step. Don't forget to do this.
6. Order A Book Cover
I usually order mine from Fiverr. They don't cost too much but they are still really good.
7. Seek Out Alpha And Beta Readers
Share quotes on social media and a sneak peek on your mailing list and blog. Whilst you're at it, ask if anyone would be interested in reading your book for free so that they can give you feedback.
8. Set Up An Author Profile On Amazon
You'll want to sell your books on amazon, so it's important to have an author profile.
9. Set up a Pre-Order for your book
Give yourself at least a month. Share your pre-order on all your social media platforms, blog and newsletter.
10. Seek Out ARC Readers
There are Facebook groups for this sort of thing or you can just ask people to do it. To get other readers you need reviews. Other people a free copy of your book in exchange for an honest review. You can use instafreebie to give your book away to reviewers.
11. Start Writing Your Next Book
Start the process again. Write. Edit. Alpha and Beta Readers. Pre-Order. ARC.
12. Promote Your Book Continually
If I was you I'd offer it for free to anyone who signs up to your mailing list.