There are many ways to take backup of wp blog i will guide you about it ... and i will charge $5 for all this
Sorry, I didn't posted in buy/sell section. you are in wrong thread . I know there are various methods which I can search at google but just want to know pros opinion.
easiest is the ftp your theme and plugins to your pc, copy wpconfig.php, go into tools and export all the posts etc. i never worry about sql backups or site backups as they simply get too messy. if a site get very messed up you may have to go into phpmyadmin and delete your wp table.. hence why you download wpconfig.....