A good pull is like having an 8th defender on the field. The goal is to get the disc as far down the field with as much hang time as possible, to give the pulling team time to run down the field, and get the receiving time starting off as far away from their end-zone as possible.
The 3 elements to a good pull are grip, spin, and power. For backhand, grip the disc just like you’d shake someone’s hand – thumb on top with all the fingers underneath. Then, snap your wrist on the release, making sure to put a lot of spin on the disc. And finally put a lot of power on the disc which will give it more distance and a longer hang time.
The key to putting power on your pull is all about weight transfer, body rotation, arm speed, and wrist snap. When you can get those pieces working together to have a smooth release, you’ll maximize the flight of the disc. Make sure to incorporate your body as throwing using too much arm can lead to injuries over time. Stretch, warm-up, and strengthen your feet, ankles, legs (calves, quads, hamstrings), hips, core, shoulder, bicep & tricep, forearm, wrist, and fingers.
Finally, you’ll need to choose which angle you will release the throw, and where you’ll be aiming. For a right handed inside-out pull, start from the left side of the end-zone and pull diagonally towards the other end-zone. This will maximize the distance, and ensure that if you do throw out of bounds, the disc will come in as far down the field as possible (as opposed to pulling from the right side of the end-zone, in which case the disc would come all the way back to where it first went out).
For a right handed outside-in pull, start from the right side of the end-zone and pull diagonally towards the other end-zone, again to maximize the distance, and to not be punished for having the disc go out of bounds too early and stay there.
For more background on pulling diagonally, check out this article on Ultimate Rob: http://www.ultimaterob.com/2012/10/03/pull-diagonally-and-have-deeper-more-consistent-pulls.