If you´r using shortcodes like [myshortcode] … [/myshortcode] there will be known issues with the html result. This Plugin easely solves this issues.
Download this WordPress-Plugin at wordpress.org/extend/plugins/shortcode-empty-paragraph-fix/
You can also install this plugin simply from the WordPress "Plugins" menu. Search there for "fix shortcode".
Without this plugin, the result of an shortcode will be wrapped by an p tag. The browsers may solves this by rendering empty p-tags before and after the shortcode result. Thats why the name.