That is not the best technique, you want to keep your effort the same the entire way up the hill. Pick a gear that you can maintain for a while. Then, as you start to slow drop down a single gear in the rear and repeat. Don't wait until you have so tons of tension on the chain, that is a good way to break it, then your all downhill and no uphill. Luckily your only shifting your FD. If you pick a gear right, you can sometimes stand and sprint up some momentum instead of dropping a gear for a while.
It is great if you can push hard gears, but sometimes your just burning yourself out. Keep in mind that if your able to spin your gears more you will be able to accelerate. What do you do when something unforseen comes along? You need to put down some power and fast, but with a tall gear you can't do that usually enless you have monster power. With a lower gear you can spin up some rpm with relative ease and get yourself through it. This applies for when the hill grade starts to increase, you have someone to pass, there are roots which you don't have momentum for, etc.
People should know there is no shame in using the granny gear, my friend seems to believe this. I love to kill him when he is being stupid with his gears. He learns and he knows why I do it.