I started last year and I did big progresses this season for two major reasons:
1) I am watching a lot of video, bought the Windsurf bible and reading, reading, reading
2) I am practicing even in the non windy week-ends, so I am in the water at least once a week
I believe that I got some advantages by buying a new sail (Ezzy) and a new board (JP 145L) but again, the main difference is how much you practice.
Also, I would suggest, every time you go out in the water, push yourself a little bit further ...

I personally wish I could get lessons.