WordPress default setting for Permalinks are not the best for SEO. The default setting is yoursite.com/p=123. Trust me you want the words from the title of your post or page, to be permalinked. This is a major advantage when Search Engines bots come to view your site, as they pick these words up and also for your readers. They can look at the top bar on your computer and see the exact words that describe your post.
To change the default settings just go to Settings then Permalinks
I use the post name, so just click on the post name button and press Save Changes. That is all, its now done.