Overall most people tend to learn better this way rather than trying to learn all Excel formulas at the same time as this can be very confusing. Most of us tend to learn in smaller packages of information and you should look for a course of instruction that will allow you to do this. As you are learning to use Excel you should of course start by learning to use the formulas that you are actually using or are likely to have need of in the immediate future.
Firstly, you probably want to learn how to type fast. Typing has become more than necessary for us in order to deliver a better quality work. You can learn typing by getting some typing software that allow you to improve your typing speed by going through sets of exercises and games. Set a timetable and stick to it. By practicing it for half an hour per day, you will become a typing master in no time! Learning to type fast will not only help you to finish your work faster but also boost your confidence to conquer the computer.