Creating a full backup of your WP installation is quite easy:

• navigate into your WP folder (best to use a ftp program)
• copy all 3 WP folders (wp-content, wp-includes, wp-admin) and all the files in the root folder
• navigate to your phpMyAdmin and export the database

That's it - so, basically, a WP backup consists of a database backup and a backup of all WP files.