Format your entry with some basic HTML. Read the Full Details, or here is a refresher:
<strong></strong> to make things bold
<em></em> to emphasize
<ul><li> or <ol><li> to make lists
<h3> or <h4> to make headings
<pre></pre> for code blocks
<code></code> for a few words of code
<a></a> for links
<img> to paste in an image (it'll need to be hosted somewhere else though)
<blockquote></blockquote> to quote somebody