What I am doing that is helping make hills easier is that my gym includes spin classes and I do two per week. The spin bike has a knob that adjusts the resistance. One of the two classes I work on hill climbing so I turn the knob until I can barley turn the pedals and I spin the pedals until my thighs are burning, then I back off take a quick breather and repeat. The second class I work on high cadence intervals. After a few months of this, I am able to climb hills in harder gears with less effort.