As other have hinted, the biggest challenge is psychological. All the technique in the world, and all the gears in the world won't get you up a hill where you've already decided you can't make it. They can't make a hill easy if you've already decided it's hard. And they can't bring you joy at the top if you've already decided it's miserable.
When I started over again six years ago, I had neither the legs nor the lungs to climb. For a long while I didn't have the will either. I actively avoided climbing. In all the rest of cycling I was willing to do the hard work to improve, except when climbing.
I'd been 35 years between bike rides and I'd smoked for all of them. The upper lobe of my right lung is non-functional due to a motorcycle accident in my youth. When I encountered a climb, my breathing and heart rate took off in ways that frightened me. My breathing frightened those around me.
My second year, on my first organized ride weekend in the Finger Lakes, I learned how truly flat it is where I live. And how embarrassingly poor a climber I was. I resolved to fix that.
I learned the various techniques of climbing. I already had the gears, and the legs had been improving, so it was only a matter of seeking out hills rather than avoiding them.
There's a wintertime group ride in town and that Christmas we were doing hill repeats out of the river gorge. Not one, but two college students on MTBs puked over their bars after the third repeat. I turned my bikepath hybrid around and did a fourth.
The following summer, 14 months after that embarrassing ride in the Finger Lakes, 27 months after first getting on a bike, I rode to the top of the highest paved road in North America.
In order of importance, what got me there were:
- determination
- perseverance
- practice/training
- technique
- equipment
Most of the advice you'll get here will focus on numbers four and five, with a bit of three thrown in. I still maintain that numbers one and two are the most important.
This weekend I began training for what's billed as the toughest century in the east, next month's the Highlander Cycle Tour. On a route where I did two repeats each of five nearby hills, my heart rate averaged 139, and topped out at 166. My L5 threshold is 167 and my max is 181. In plain English, it was a challenging, but comfortable ride.
And I did it with a standard double and my 12-23 "flatlander" cassette.