The WordPress SEO plugin is, quite simply, the best SEO plugin available for WordPress. If you use this plugin, you will probably not need any other SEO plugins. The author, Yoast (a.k.a. Joost de Valk) is a highly respected WordPress and SEO expert, and his plugin gives you the tools necessary to effectively optimize your WordPress website.
Search engine optimization is generally easy with WordPress, once you understand the basic principles. You don’t have to configure any special settings to get your website crawled by Google. And from a technical standpoint, WordPress is a very search engine friendly solution. The Genesis themes, which we use at EfficientWP, give you some advanced SEO functionality beyond what most WordPress themes offer.
Of course, search engine rankings are far from guaranteed, and the more SEO work you put in, the better the results.