The best practice for a blog article is to include a short sentence or two at the top which will act as a summary / teaser for your article, and then put a “More” tag after this line. (The line you are reading right now is this summary. Edit the article to see how this was built.) This tag tells WordPress to cut off the preview of the article on the main list at this point. When the full article is loaded, the more tag is hidden and the full article displays. This gives you better control over what users will see when they first arrive at your blog.