When you arrive to your website - the thing that will probably strike you the most is the big, red "List me!" button. But what does it mean to be listed, and how can a site qualify for listing?

To have one's site listed means that the platform's administrators have approved the content which can be found on the site. This doesn't really apply to the nature of the content itself - but rather to the minimum amount of it the site needs to look complete and ready to welcome visitors. While in unpublished mode, the site is only visible to the owner and the platform administrators, which means no other member or guest can view it anyhow. Once you've filled your site with content, clicking the "List me!" button will signal the administrators that you've prepared your site for going live, and it will be reviewed shortly. If your site is disapproved for publishing, it means that it probably hasn't met the minimum content amount criteria.
In general, rules are clear for determining what site needs to be considered ready for publishing.
However, even these requirements are not that strict. What really determines what your site needs to have is its Layout. In this case you only need to upload the content which is relevant to your field of work.
For instance, if you only wish to focus on writing blogs - you can pick the "News" or "Max News" site layout. If you're a visual artist, you might not want to write as much, or write at all, which would make the "Gallery" layout a logical choice for your website. If you're mainly uploading video content, you can choose the "Video" layout.
Mixed layouts like "Max News Gallery" or "Max News Video" put different types of content on the Home page, making them more appealing, but also more demanding to satiate.
Whichever Layout you opt for, you need to disable the Home page sections you will not be using. You can do this through the Control Panel.

If you feel like adding some other types of content later on, you can always re-enable these options at any time.
Another thing that may serve as guidance is demo content - when you replace demo content with your own, your site is sure to be approved for listing!
In general, a site needs an overall sense of minimal realization in order to be published. Once live, site will be visible to both guests and Althemy members, and ready to welcome your target audience.