Get a mudhugger on the rear, a crud catcher on the downtube and a fork mounted mudguard on the front.
After each ride, clean it straight way (while the mud is still wet) with a Mobi Jet Washer. These are mobile so if your ride ends at the car, it is still not a problem. it does however require the full 17 litres of water if you want to clean everything including the wheels and frame.
The Jet Washer in itself cleans everything, sometimes spray some washing up liquid on the bike to speed things up.
The only thing that requires additional attention is the drive train.
Going 1×10 also seems to help with the gears, gets much less problems, as there is less moving parts for the mud to wreck.
That’s all I ever do and thats with a full suspension bike and it doesn’t usually need much replacing over the Winter. 200-300 miles per month November-March.