the techwax is good. but dont be fooled (and dont get me wrong, i like meguiars) it doesnt remove the scratches/swirls, it fills them. once you wash the truck theyll come right back.
theres nothing you can spray on your truck to protect the finish. theres the 3m clear chip guard film, but that stuf is a huge pain in the ass. DO NOT ATTEMPT TO DO IT YOURSELF!
as far as inexperience with an electric buffer, yes you can burn the paint and the only way to fix that is to repaint it. the technical way it removes scratches is it heats up the clear and cause it to "level out" if you heat it to much youll burn it (turns white, forever) hand buffing works but isnt as fast or effective cause you cant move your hands at 1400 rpms.