This was a great online course by Yves Leterme. Beginning with improving our italics skills, through making variation in letterforms, letter connections, rhythm etc. the final aim was to get to real gestural writing.
This one really takes you to the next level and the difficulty rises faster at the end. I found myself copying Yves from the videos letter by letter, stroke by stroke and that helped me the most. And of course you can't make it without regular practice.