As a reluctant ex winter commuter in ALL weathers, extreme weather is heavy on the bike, here's what i found and did..mostly in extended really wet, salty conditions.
Alloy steerers, brake nut recess hole.. .crud and salt can collect in there and cause corrosion. I smeared antisieze liberally in that area to deter it.
Wet gritty salty weather, flint and grit collects in the brakepads...potential to scour your rims. Mine got damaged quite noticeably. Regular inspection and dig out grit with a stanley blade or similar.
Sora 8 speed front mechs are prone to siezing with corrosion. Quick to fix with a spray of WD on the pivot.
I kept a spray bottle of light detergent at wotk and some paper towel. I'd spray the frame and wheels then wipe dry. Takes two minutes. Amazing how dirty the rims get in dirty conditions.
Personally i antisieze anything i can, thats any nuts and bolts, seatpost, barrel adjuster bosses on the frame, calipers...had them all sieze at one time or another...but not since ive applied antisieze.
Wipe chain down with a coth ASAP after ride, apply oil as regular as you feel neccessary.
Quick spray with WD on mechs, calipers ASAP after ride, wipe down with a cloth.
Sounds a lot, but 2 or 3 minutes wiping and cleaning after rides can keep your bike in good condition.