I have mostly been shearing a massive taxus hedge in front of the Enid A. Haupt Conservatory.  This beast is long, and about 70″ wide.  I have a pair of shears that aren’t the greatest, and have spent a lot of time doing the back of the hedge (it isn’t that visible).  Anyhow, I’ve been taught to go along for a length of hedge and mark the depth you want to cut, then cut in the top and progressively move to the bottom of the hedge.  All the while, be sure to back up often and look at what you’re doing.  I have the habit of putting in a “belly” at about the 2/3 way down mark, so I usually have to go back and straighten that out.  NYBG is very exacting with their hedging and this is taking a long time.  The thing that is the worst with this process is when you make a sharp cut and hit a knuckle or thick branch and the shears vibrate in your hands – that hurts a little, and it happens often.