Hi Mike,
In general terms, what makes a good roll or Spey cast is minmal anchor that is straight and in line with your intended target, important too that the D loop is in line.
It is much easier to demonstrate than describe but here goes (assumes neutral wind and no heavy current with a floating line)......
Raise the rod tip to approx eye level then cant the rod to about 30 degrees from the vertical and draw the line back into a D loop. The line should be straight as it is coming back towards you, when the end of the line and leader has stopped moving, you have lifted as much line as possible from the water into the D. Your hand should be about level with your ear and your wrist should be cocked at about 45 degrees, about a 4 finger gap between the rod butt and your wrist.
The delivery should go something like, working form the above position, make a lift up and back into the D loop and then come forward by "pushing" the rod forwards towards your target whilst maintaining the angle between rod butt & wrist, push the rod forwards using the straight flyline on the water as a guide, you will be leading with you elbow and have a light grip on the rod.
When you effectively run out of arm and cannot push forwards any further, rotate the rod sharply and give the grip a squeeze immediately pushing the tip up into the forward loop, stop high, this should gve you a tight loop.
Cheers
Ben