There are a number of things authors can do to establish themselves and get the word out about their work but if you are having some trouble finding something to do other than spam your friends and family on Facebook there is always the option of getting a PR expert to help you. PR stands for Public Relations and they help to promote companies and products making them more visible and in appropriate light for the public.
Public relations has a bad reputation in some circles as "spin specialists" meaning that they take information and turn it around to make people believe something is good even when it is not. I will admit there are those out there that use it for such reasons but the majority are simply interested in helping promote and finding proper channels for their clients to get noticed.
Please note that if you are self publishing and are concerned about cost it can be somewhat expensive to hire someone to assist you in marketing your book. There are groups that you can turn to to make sure you find a reputable one with a little research if you do desire the help. You can always ask for recommendations from friends and family, talk to local businesses or chambers of commerce or you can check out the members of the PRSA or Public Relations Society of America.
Another option if you decide you want to work with someone but determine you are unable to cover the fees for their services is to contact a local community college or university and speak with some marketing and public relations students or instructors. If you can find students that are willing to help they make give you advice for a significantly lower fee or you could speak with an instructor who might have some ideas and even be able to point you to someone in their classes that would be interested in taking on the project possibly for some extra credit.
However you find them, if you end up working with someone pay close attention. They can help you see things that might have worked for others but are not in your best interest while pointing out avenues that you had not previously considered. If you are working with a student or college professor, take notes. They most likely will only be on your team a short time but can teach you ways to think outside the box that you can then carry forward.