When you reverse-engineer someone else’s code, testing each line to see how it works, you get a better understanding of the big picture. Thanks to the tons and tons of open-source code that’s out there, you can learn just about anything by examining someone else’s (flawless) work. Just remember to share your code back with the community if inspiration strikes and you improve a part of the program you were fiddling with.
It is more important to have a low error percentage than a higher speed. The low error percentage will be your best guarantee for success in the following lessons. You can follow your progress at the statistics page (just press the button 'Statistics' at the upper right corner) You should strive to do all lessons flawless (or at least with max two percent error) before you go on to the next lesson. If you learn to type flawless a high typing speed will automatically ensue. By the way, the error statistics will only save your best results.
EdX is another leading online-learning platform that is open source instead of for-profit. It was founded by Harvard University and MIT in 2012, so you know that you’ll learn about cutting-edge technologies and theories. Today, edX includes 53 schools. You probably can’t go wrong with the free Introduction to Computer Science from Harvard University.