Well, first off, buy new supplies for the black car and only the black car. Get yourself a 5 gallon bucket and a grit guard (keeps wash mitt out of dirt in the bucket).
For washing, pre-rinse thoroughly- I prefer using a pressure washer so I can get wheel wells and stubborn dirt. (Others will say a pressure washer is bad- I have used them for 7 years on cars without any issues- just be careful and use the softest nozzle).
Use a sheepskin mitt (NOT FROM WALMART or AUTOPARTS STORES!!! they have plastic fibers in them) Buy a good one online at one of the many detail supply places.
After a good wash, I always use an air chuck or leaf blower to get all of the water out of the gaps- ESPECIALLY the mirrors on the '05+ Mustangs.
For drying, I spray the panel with Eagle One "Wax as you dry", then wipe the large beads with an absorber, and finally, dry with a waffle-weave towel.
And, I don't car what the ZANO site says- don't go near black paint with a terry towel- no matter how soft it is...
Never get lazy with black- even washing it once with the wrong supplies and it looks bad. Not washing your car at all is better than taking it to a car wash- don't even get me started on car washes-
Also, wash your towels for the car separately, with liquid soap, and air dry them. (If you wash them with household towels, they will pick up fibers/dirt that can/will scratch your paint. Air drying them makes them last a lot longer).
Here are the results after a year with the Shelby- and yes, it's a daily driver in the rain, mud, dirt, etc.:
Any more questions, feel free to ask!
Few more things:
Carry a detail kit in the trunk- if your car sits out all day and gets bombed from birds, the bird dropings will burn through the paint- especially on a black car.
No matter what you use to wash your car, start at the top and work your way down- for every step of the process.
The yellow towels are good for door jambs- but don't use them on the exterior of the car- they leave minor swirls. (learned this on my '04).
The bag of microfibers from Costco are cr@p- they do more harm than good.
I personally don't like microfibers at all- they collect too much stuff- even when washed separately. If I do use them, I get the 3M brand for about $5 each.
I have been recently using products from production car care products. www.cleancarproducts.com . I use the Midnight Special, its designed as a hand or buff polish for black and dark paints. I follow it up with thier new car polish spray detailer. I actually just did the car a half hour ago. This stuff makes my car shine like no other product has, it also hides alot of "imperfections" . Just my 2 cents.
I never dry the car after I wash. I usually just let it air dry in a closed area like my garage during the summer.
When I took in the black E-250 for the factory paint delaminating from the hood, the dealership told me that I bought the "wrong color." Black is extremely hard to keep clean and doesn't look as sharp as metallic or pearlescent paints. I didn't have much choice when ordering the E-250 because the other colors looked like a$$.