Watch American movies, imitate an English teacher from America and stay away from the brits. lol (kidding guys)

I second Dark Panther's suggestion: search out music, films, tv series from the USA and practise using those. Get the real stuff! :D Trying to follow a written description would make you sound very strange.

Tis rather simple, you just have to learn to talk like a hick. Just kidding. But really, american pronunciation is not much different from Canadian. There is a few things they say differently. for example. we say " ve-ihkle" ( vehicle), and they say "ve-hickle" (vehicle). or we say " you all" and they say "y'all" ( you all) lol. That's the one bad thing about american english, they use to many slang words and have funny accents lol (especialy the southerners) lol