After you install your wordpress blog it is time to install plugins for best blogging experience.
There is a plugin directory on the offical wordpress site, wordpress.org at this address: https://wordpress.org/plugins/. You can also head to WordPress admin account panel and click Plugin tab, search and install from thousands of available plugins. In my opinion the following plugins are the best and recommended to install when you create your blog:
wp-super-cache
Wp-super-cache is an excellent cache plugin that generates static html files of your posts, categories, pages and other. After a static html file is generated it is served the next time the resource is requested. This will lessen the load of the wordpress hosting server and will allow your blog to stay up when traffic spikes are here, (e.g when your post hits digg.com front page). It is a must install plugin.
Google XML Sitemap generator
Google XML Sitemap generator will allow you to generate Sitemap XML files for google. This will allow faster SE (Search Engine: Google, MSN, Yahoo) indexing of your site’s contents. Faster and better indexing is better and it might increase your rankings.
All in one SEO pack
All in one SEO pack is a great plugin, that generates and adds automatically meta tags and meta description, generates titles, tunes overall SEO (Search Engine Optimization) for your blog. This will allow better indexing and it may increase SE rankings.
There are lots of other plugins available and you might want to install them if you need additional features. Some also recommended are Contact form 7, Google Analycator and others.