There are many elements to a website, or more specifically to ensuring that it runs smoothly. Your server needs to be connected to quality bandwidth, and you need to load your content efficiently. One easy way to do that is to use caching. What caching does is this: it stores a page’s content and serves it in a manner that reduces the stress on your server, and in so doing, it increases the speed for your site’s visitors.

One strong product that caches content is WP-Supercache. You can download it directly from the WordPress plugin site by visiting the profile for the plugin.
Installation is quite easy; after downloading it, you’ll want to upload the wp-super-cache folder to your plugins folder in WordPress, which can be found within your wp-content folder. You will then need to go to your plugins page, and activate it. You’ll want to make sure that your .htaccess file is writable, so that the plugin can make the necessary change. You will next want to look for a “cache” folder within your wp-content folder. Go into that folder, and look for an .htaccess file. If none is there, you will need to make it yourself, and ensure that it reads as follows:
BEGIN supercache

# END supercache

If everything has been done correctly, you will be caching at this point, which will result in a noticeable increase in speed when serving web pages. This comes in particularly handy with WordPress, as there is a lot of code involved with PHP. It also will reduce the stress on your database, and it will serve you well when you’re hit with a sudden increase in traffic.
If you run into problems with the installation, consult the installation instructions in the link above. Most of the time, problems arise due to simple coding errors, and the situation is easily remedied.