Is FCW keeping your score low?
Yes -> good plan, miles driven on AP will dilute the FCWs-per-1000-miles score and increase it.
No, it's something else -> miles driven on AP will not add any good points to dilute the bad, and you'll just accumulate bad marks from driving manually only for tricky merges and immediately engaging AP which masks any good points.
To increase following score, drive manually whenever it's clear and you can follow someone while counting following seconds to stay in that 1-3 second window.
To increase braking score, just brake a lot with full regen. More seconds spent fully braking with regen = more good seconds to increase your score.
To increase turning score, general idea is to take road curves that have a yellow "curve ahead" speed limit sign at +5mph or so. Traffic turns I find best at 15-20mph. That's all about butt calibration... no good way to classify it, but if you take it too slowly, it doesn't count.
Enjoy the drive!