Ill give you my method. Bare in mind this is how i wash the car based on the fact ive sealed the paint.
The key to washing any car is in the prep for that half of the year.
In all the years ive been fettling with cars ive learnt this the hard way.
Now i will spend 3-5 days prepping the car for summer or winter.
I do have the benefit of a garage which gives me the flexibility to let things cure, work all day in the dry etc but the washing methods below i think ensure minimal to no damage to your paint and an awesome finish.
Also one thing i would advise if you have space is a water filter tank.
Just means that you can leave your car wet and it wont get water spots which are my kryptonite.
Lastly, find the right products for you.
You will notice that in my winter washes i dont physically touch the paint.
Only the wheels will get touched and only if heavily soiled.
If need be i will drench a wash mitt in soapy warm water and wipe in one direction any heavily marred or watermarked panels, otherwise the paint is left alone and as its protected by the time the wax gets strippied for summer, theres no damage, swirl markes etc etc and easier to decontaminate.
Summer:
Clean wheels (fallout remover, wheel brush etc)
Rinse with 0ppm water
Citrus pre-wash
Jet wash
Snow foam
Jet wash
Rinse with 0ppm water
Wash with two mitts and two buckets
Rinse with 0ppm water
Wet Wax topup
Rinse with 0ppm water
Pat dry with plush towel
Winter:
Clean wheels as above
Rinse with 0ppm water
Citrus pre-wash (stronger concentrate)
Jet wash
Snow foam
Jet wash
Snow foam
Jet wash (yes twice)
Rinse with 0ppm water
Wet Wax top up
Rinse with 0ppm water
Dry with warm air dryer