Alex, if you mean "how do you get more pages of my site to show up in Google search?", my answer is specifically for you.
1. Are you experienced in doing keyword research?
If so, you should use low competition keywords within articles on your site. This will quickly be picked up by Google and your site will be indexed. Do not overstuff keywords, use once in the title, naturally. This works well for our own sites.
2. Site map
If you have about 15 pages or even 30, your site should have a site map. To get one on Wordpress install [URLnf="https://wordpress.org/plugins/simple-wp-sitemap/"]this plugin[/URLnf] and copy the "sitemap.xml" address it gives you into Google Webmaster tools. Now Google will make sure to index your pages.
PS: Google does this anyway, but adding a site map to GWT may help and is usually advised.
After doing 1 or 2, you should see more of your pages eventually get indexed. Google Webmaster Tools actually reports when your pages get indexed. I believe indexing occurs for different reasons: sometimes because there is a lot of new content on your site being added, sometimes because the content is well structured (media, header tags, high quality writing, cited sources, good spelling, etc) and sometimes because there is linking activity from sites that are well linked up on the internet. These are my suppositions.