They seem to struggle with doing pull-offs with the right hand fingers.
If you have access to the lessons on GT, try looking at Kevin Taylor's tapping tutorials.
http://www.guitartricks.com/lesson.php?input=1873
http://www.guitartricks.com/lesson.php?input=1961
http://www.guitartricks.com/lesson.php?input=2059
http://www.guitartricks.com/lesson.php?input=2484