Just thoughts after a quick scan~

Cadence sensor great, but don't kill your self over the people saying 80 or 90. Figure out what your current natural is (mine was 60) and try to improve on it incrementally. If you force yourself to make too big of a jump too soon, you just waste energy. It took half a season for my average to go from 60 to 70. But all the advice about shifting to keep your target cadence is spot on.

When you see a hill, pick a strategy and set your front based on that. If it is a big ring power over hill, then commit and do it. If it is a granny spin, then commit and do it.

The best way to throw a chain is to shift the front under load. If you think about it, the top of the chain is the portion under load. So your FD is working on tensioned chain, and your RD is on slack chain. Always plan to shift the rear in strenuous situations (you should still soft pedal but its way more forgiving), and not the front. If you have to shift the front, do a few hammer strokes, then soft pedal and switch.