Most mainstream publishers do not accept book submissions from authors who do not have an agent, with the exception of children's picture books, in some cases. Independent publishing companies, like Alice James Books, Ampersand Books, Broken Pencil Press, Howling Dog Press, Moon Tide Press, Ridan Publishing and Seven Stories Press accept unagented book submissions from aspiring authors.
Each publishing company has a different submission process and usually posts guidelines on the company's website. Ridan Publishing, who publishes mostly works of fiction, requests a cover letter, a one-page synopsis of the novel and chapters 1 through 3 or 50 pages of the novel, whichever has the least amount of pages.
Most magazines hire a portion of freelancers to help churn out a variety of exciting content for each issue. Although some magazines hire more freelancers than others, there is a plethora of magazines that frequently accept pitches from freelancers, including Real Simple, Home Digest and Home Cooking Magazine.
Additionally, some websites that are not associated with a print magazine or newspaper accept submissions, including Slate Magazine, Nerve.com and Gothamist.
Choose to pitch to magazines that focus on a topic that interests you--and one that you have a background in. Usually the editor-in-chief, or the editor of a particular section if it is a larger magazine, will handle pitches from freelancers. Find the email address of the editor, then pitch a story that you feel would be a good fit for the magazine. Read a few issues of the magazine before submitting, so you can tailor your writing to the style of the magazine.
Although anyone can be published on the Internet by creating a blog or personal website, you can also get in your favorite magazines by submitting articles to their websites. Some magazines will publish additional content on the Internet, which might lead you to more lucrative publishing opportunities in the future.
If you are looking to publish fiction or poetry, glossy magazines might not be a good fit for your work. Universities and other private markets publish literary journals that pay, sometimes handsomely, for poetry and short fiction. Although some literary journals only accept submissions during a portion of the year, submitting your work to journals like the Boston Review, Glimmer Train and the Kenyon Review can help bulk up your resume, while giving you some extra spending money.