The kinds of typing errors
Substitution, transposition, omission, doubling. Each has a different cause and a different fix.
Tag
practice
Warming up
Two minutes of slow typing before any session improves the rest of the session.
Typing code
Why code is harder than prose, and how to drill the symbols you actually use.
Fixing the pinky
Why the right pinky lags, and how to bring it up to the rest of the hand.
Plateaus
What to do when your wpm has not moved in a month.
Daily practice
How long to practice, what to practice, and what to do when you do not feel like it.
Accuracy before speed
Why every typing tutor tells you the same thing, and what it means in practice.