I would just like to re-state that in terms of grip one of the keys is not to try and fight the recoil. Many shooters think that in order to shoot shots quickly, they need to prevent the gun from recoiling. Not only will fighting the recoil mess up your accuracy, it will actually slow you down.
If you let it, you will subconsciously return the gun to the point of aim after recoil, and you will do so quickly.
Load two magazines and fire each in turn at a single target as quickly as possible. Do the first ten shots trying to eliminate the recoil. Then do the next ten shots without fighting the recoil and just letting the sights come back into aim on their own. It may take a little practice, but you should find that the second technique is not only a lot less stressful but faster and more accurate.