Find a hook for your song. The hook is the part of a song, usually the chorus, that makes it memorable and catchy. While you can begin to write a song by starting with any component (lyrics, bass line, beat, harmony), the hook will most likely be the first element that occurs to you.
Write the lyrics (if applicable) to your song. If you are going to publish and sell or distribute your song online, consider publishing the lyrics on your own website as well so that fans can see your words.
Write a chorus and several verses for your song. Most songs also include a bridge, which happens once in the song and acts as a break that connects the last verse back to the chorus.
Record your song. Depending on the instrumentation, this may involve setting up simple recording instruments in your own home, or renting time in a local recording studio for a full band. Download the final recording onto your computer as an MP3.
Choose a self-publishing website with options for musicians, such as Lulu or CreateSpace, and register for a free account by entering your name and email address. Log in to your new account and click the option to start a new project.
Choose the "CD" or "Album" option from the media section, and enter your name (or your band's name). Most websites will offer you the option of making your CD available to the public or private at this stage, so check "Public" to be sure your song is published online.
Click "Browse" to find the MP3 of your song on your computer and click "Upload." The website will offer their own unique options for ordering, such as whether the song will only be available for download online on this website or websites like Amazon, or if you'd like an actual CD made.
Scroll through the website's cover art options. Most websites will allow you to upload a design from your computer, or you can choose from one of their pre-made templates. Click "Save."
Enter a price for your song if you plan on selling it online. Follow the website's instructions to order a copy of your CD to preview before you sell it.