Marketing a book

I have but I had a bit of a head start because I had already had articles published in some magazines.
They agreed to review my book.

Some magazines do what they call "give aways" or something similar, where they will publicise a product that their readers can win by sending in their details to the magazine.
I offered a couple of copies of my book for the magazine to offer to their readership.

This helps the magazine because they obtain the readers details and it helped me sell the book because some readers don't want to wait to see if they will win a copy, so will buy it straight away.

I don't know if your book is fiction or not (mine is non fiction) but a magazine that publishes a number of stories might be willing to advertise a "give away" of your book if it is fiction.

Try contacting local newspapers and radio stations and ask for phone interviews. Local groups may like you to talk to them, not just about the contents of your book but how you went about it - plus all the self-publishing details.

You can sell direct on Amazon.