I suggest using a good quality spur wheel such as those from Howe Press of Perkins School for the Blind. I use a metal ruler with cork backing, so that the edge is [u]slightly[/u] raised from the paper, preventing the spur wheel from "catchinng" on the ruler. I also use a neoprene matt to work on.
I do know that some people manage better when they "push" the spur wheel away from the bottom of the page, but I have found that I need to "pull" it down towards the bottom of the page. When moving in a circular motion, I rotate the mat and paper periodically while keeping the spur wheel in place, rather than lifting the spur wheel and starting again.
Remember, practise makes perfect!