You can improve your touch typing using Typing Club, a free typing program. This online program will assist you with learning and improving your typing speed. Choose the keys or general practice session you want to use.
After completing the session, you will get feedback on your performance based on speed, accuracy, characters typed, fingering, as well as speed over time as shown in the screenshots below: (click images to enlarge)
Performance on each character:
Timeline of typing speed:
Typing Club also has a Chrome extension so can you can download it and use it right from your Chrome apps.