Originally Posted by Roarau

Power, power vs. cadence is the key. Your power and cadence should remain stable regardless of the gearing you are in. Eventually you should get to a point where you can feel the numbers on a training ride. Where, you know what 85-90 cadence feels like, so you won't need to check often. Pick a power number and stick to it, uphills, downhills, flats, headwinds, doesn't matter, stick to that power number.