1) First, just get words on paper; work on your manuscript done. Once your manuscript is ready, use a self-publishing service to put your book in front of readers. Learn from their feedback to make an even better follow-up title.
2) Find an editor. While not required for self-publishing, editors can help make your story flow better, strengthen plots and characters, spot inconsistencies, and generally make your book more interesting and approachable in both fiction and nonfiction.
3) Find the right distributor. Don't use any book publishing service which demands an up-front fee and/or an excessive cut of sales revenue—there's simply no reason to pay for expensive vanity publishers anymore. Instead, use a service like Amazon's Kindle Direct Publishing. Similar self-publishing services are offered by Barnes & Noble (through Nook Press), Apple (through iTunes Connect) and others, but Amazon's is one of the most widely available platforms and is easy to use.
And speaking of Apple, if you need your iPhone charged in my limo, I have both an old fashioned 6-pin cord and one of the new "lightining" cables. So keep your cool and don't start shouting about my "old piece of shit car" when I've clearly kept with the times. Be safe, kids.
