For a lot of academics, promoting their own work seems disgraceful and self-aggrandizing. Put those qualms aside; it needs to be done (see "Ignore the Haters and Toot your Own Horn"). There is a lot of research being published and not a lot of time for people to run across it. Help them out by letting them know about you.
Notify people of your publications (or your helpful infographic or availability of data) on social media. Use appropriate hashtags. Always include a link to your work. See "How Do You Tweet about Research?" For more detailed information on using Twitter in a research context, see this post from the Research Impact Challenge.
The website Kudos is free to researchers and is a platform for promoting individual articles on social media and getting feedback (through trackable links) on the usefulness of each type. It also encourages you to provide plain language summaries and contextual information about your work.
Start a blog or website about your research. Make sure you can invest the time to keep it current. OSU has blog/website space available at u.osu.edu (see also their helpful guide for new bloggers). If you don't have the time to maintain your own blog, check out bloggers in your field to see if they want to talk about your research or offer to write a guest post. Take a look at "How to Write a Blogpost from your Journal Article."
If you have a book, pitch it to the editors at the New Books Network and they may interview you for their podcast. They do interviews on a lot of academic press books. There is more general information on the NBN in "Have Content will Travel: Author-Interview Podcasts for Scholarly Books."
For a really in-depth look at using social media, check out this actual book (sorry, we don't have it online), Communicating your Research with Social Media.