Hello, @francoday!
An average typist should be maintaining an accuracy rate around 92%, or about 8 mistakes per 100 words. To improve on accuracy, slow your typing to focus more on typing correctly rather than quickly. As your amount of mistakes lowers, only then should you be pushing for a higher WPM. And, as with anything typing related, the key is practice, practice, practice!
It has been a while since you posted - have you had any luck? Any tips or tricks you’d care to share?
Regards,
Alex (The Reimagined Classroom Teacher)