My form was not perfect before taking the class. I would often do something slightly weird with my right hand where my it would "walk" to slightly incorrect positions to reach keys that my other hand should be hitting.
My typing teacher put covers over the keyboard so we couldn't see our hands and then had us do typing drills. She would strictly enforce that we maintain our hands on the correct home-row position, wrist positioning, etc.
After a semester of this class, despite an initial drop in my speed, I can now touch type correctly and my speed is now faster than ever.
I work with professional programmers who hunt and peck and it drives me crazy. For something that you interact with daily and is the instrument of your profession, taking an hour a day for a few months is a no brainer to perfect your form.