What really helped me improve my typing speed is competing with my friends.

When my fingers hurt after too much time on the keyboard, I... tape 'em up.

My tip to improve your typing speed is to type much faster than you are typing at the moment. If you manage to always type faster than you used to, then your typing speed will almost definitely improve.

When my fingers hurt after too much time on the keyboard, I turn to hard drugs.

When my fingers hurt after too much time on the keyboard, I rub linseed oil into my forearms.