I've been writing pretty much every day for the last five years at least, and regularly for three years before that. I now write around 1000 words a day, which I then critique and edit. Usually I spend 2-3 hours a day practising my writing. I have also done a number of courses and regularly request assessments from qualified teachers. My point is the best way to improve your writing is to write, critique assess and rewrite. Everyday.