Check out this great video which covers a no nonsense and effective approach to learning (and improving upon) speed reloads. A three step procedure is covered in this video:
1- Activating the mag release while simultaneously drawing a fresh magazine.
2- Visually acquire the magwell and insert the fresh magazine [done within your "workspace"].
3- Rotate pistol out toward the target and reacquire the sights.
While I am nowhere near as fast as the instructor in this video I feel compelled to mention a few points. There has been some debate as to whether or not one should look down while inserting the mag, no matter how brief it might be. I for one do this, but according to some that is a mistake because I take my eyes off of any potential threat downrange. To each his own, do what you feel you can get away with (or what is comfortable for you). Additionally I would encourage those who are newer to the game to not get frustrated if, after 5 trips to the range you cannot speed reload with the type of efficiency demonstrated in this video. Remember you can always conduct dry fire drills from the comfort of your own living room in order to build proficiency.