I followed this advice, I used document.querySelectorAll() with a .slice() hack instead of jquery and similar methods. As I needed more and more functions I kept adding them, and now I have a beautiful jquery alternative [1].
It has helped me a lot to learn core Javascript concepts, testing my code and hating Internet Explorer even more. I wouldn't change everything that I have learned for anything. So try it, create your own small library, you'll learn a lot.