One of the key skills that you need to master if you wish to learn how to to repair flat screen TVs or any electronic devices for that matter is the skill of soldering. This video series courtesy of Pace Worldwide provides the basics on the really fine art of soldering. It is a 9-part Youtube video actually that covers a lot of aspects of soldering for electronic circuit boards and should be watched by beginners. Although the video seems to have been shot some decades ago, the techniques shown are as relevant today and there should be no problems applying them today.
You can watch all 9 parts of the video below or you could go watch them piecemeal, 1 lesson at a time (look further below for the links to each lesson):