Start up each hill in one gear lower than you need.
Let’s say you come to a hill that you usually begin in your 39×19-tooth gear. On a good day you make it to the top in this gear, but sometimes you don’t. You have to shift to the 21 cog or even the 23, and you really slow down.
Today, start up in the 21. Yeah, it’ll seem too easy. But raise your pedaling rpm and you’ll keep your speed.
In the 21 your legs will feel fresher longer. It’s not likely you’ll need to shift lower. In fact, as the crest comes into view, you may be able to click into the 19, give it the juice you conserved, and reach the top with increasing speed.
Legendary coach Eddie B once described it this way in his classic book, Bicycle Road Racing: “Correct climbing is a matter of increasing your gear, not decreasing it.”
This can’t happen unless you start in an easier gear than you can handle. Try it and see. It works for racers and for anyone who wants to control hills instead of letting hills control them.