My tip to improve your typing speed is to...do not worry on improving all of a sudden. I've waited a month, typing constantly in non-competitive, non-stressful situations and my average improved by 10 WPM, your speed improves on its own :)

What really helped me improve my typing speed is improving accuracy and not being demotivated when there is a dip in speed. Every dip is followed by a peak and every peak is eventually followed by another dip.

Try out instant death typing tests and pepper throughout normal tests to improve your accuracy and making you consider every single letter typed.