Help!!!!!

I have been playing snooker for about 27 years to a reasonable club level, and I was introduced to Billiards in June last year. It seemed that I picked up some of the basics and was asked to play in the Hurst Green summer league, which I enjoyed with some success and I somehow beat a few of the more established and experienced players. But since then I have been looking at various videos and was given your book for Christmas, but I seem to be going backwards in my development in the game, I am struggling to master the half ball which, seems to be the most important aspect of the game. Do you have any tips?
Looking forward to hearing your thoughts
Ade