This is the reprint from a G35 forum I frequent. I've been using his method for washing my car for years and it really helps cut down on the swirls. Before I paste, I want to summarize the two most important tips in this post (in case you get bored and don't read the whole thing)
1) Use multiple wash mits on different parts of the car (at least one for wheels, rockers, lower trim and anotehr for main body panels) and rinse them in CLEAN water everytime you go back for more soap - that means two buckets, just like your grandma does the dishes.
2) ALWAYS move your wash mit, drying towel, whatever touches your car, in a back and forth motion, from the highest to the lowest point on each panel. Imagine letting a drop of water hit your hood, whatever direction it runs, that's the way you should be wiping - example: up/down on your doors, back/forth on your hood - the idea here is that, no matter how careful you are, you WILL be putting some minor scratches on your car. If you always move your pads in teh same direction, and move them in a way that minimizes the direction sunlight is reflected, your "swirls" will actually be only straight marks and will be MUCH harder to see.
Ok, on to the post. Source: http://g35driver.com/forums/showthread.php?t=141057
OK, so maintenance. Now this is even more important that polishing. Why? Proper maintenance means less polishing is required over the life of the car. You want to wash and seal/wax in ways that DO NOT scratch the car, thus eliminating the need for polishing. So, the most important part of car care: how do I wash?
I wash in two ways, either the regular bucket + hose way, or with a rinseless wash. I will go over both.
First, bucket and hose. OK, products I use:
One or two buckets, both with grit guards. You can get them at CT (red, $15.99)
At *least* 2 sheepskin wash mitts. Why 2 or more? you'll see.
A good automotive soap. What's good? Most are; Meguiars deep crystal is cheap, locally available, and good. JUST DON'T USE TOO MUCH OR IT WILL STRIP WAX. Use the quantity directed, don't just pour a bunch in the bucket. Remember, as nice as suds are, too many = too much detergent.
2-3 good microfiber drying towels.
5+ good microfiber clothes.
A good all purpose cleaner and/or bug remover. I like poorboys apc 2:1 with water or bug squash 3:1 with water.
A wheel cleaner and sealant
So, so let's start:
First, the wheels. I only use a wheel cleaner if there is a significant amount of brake dust. What wheel cleaners do I like? The best, imo, locally available are Eagle One All Wheel & Tire Cleaner (caustic), or for less acidic/caustic, their aluminum wheel cleaner. A lot of you have P21S cleaner; use it when needed, it's great stuff.
Put the car in the shade. This is important. If you're using two buckets, fill one with soap and water and the other with just water.
If the wheels are dirty go to step 1, if not, step 3:
1) Hose wheels off (make sure they are not hot). Spray wheel cleaner on wheels and let dwell. Agitate with a brush (a wheel brush, not a tooth brush or a carpet bursh) or an old wash mitt, or an old mf cloth. Something soft basically.
2) Hose off, if there is still dust repeat. Go to step 4
3) Wash with soap and water (the automotive soap) and an old mitt.
4) If you washed with your bucket water, dump it out and re-pour it. Wheel dust in the water = don't put it on the paint, EVER.
5) Soak one mitt in first bucket with soap. Not all of them.
6) Rinse the car. If it's very dirty/buggy, apply liberal amounts of diluted APC/bug remover to effected areas and let sit.
7) Get the mit and start washing. Use almost nopressure, start at the top and move down. So roof, front and rear window, side windows, upper side panels and fenders, hood, rear deck lid, trunk, lower side panels and fenders, and finally rockers. Why? The lower part of the car is almost always dirtier, you don't want to use the mitt on them then move it to the cleaner areas. Now, don't do this all at once. Do it like this:
8) Wash roof and front and rear window. Put the mitt in the clean water bucket and thoroughly rinse it out. Put it back in the soapy bucket and wash the side windows and upper side panels (doors, fenders), then back into the water only bucket, rinse... see the pattern? Dirt gets rinsed out. As the mitt gets more and more dirty put it aside and USE A NEW ONE. I use 3 per wash almost always. One for roof, windows, upper side panels, one for hood, read decklid and trunk, and one for lower side panels and rockers.
9) if its hot, rinse the car often; keep it wet at all times.
9.5) Put the hose over the roof and let the water flow freely over the car. This will "sheet" water off and make for about 80% less water on the car to dry.
10) Now dry. How to dry? Take one towel and spread it on the roof then slowly move it the same way you washed (top to bottom), DO NOT worry about getting the car dry at this point, you want to remove most of the water but leave it damp.
11) get towel two and finish any areas you missed, then re-dry the entire car to clean up the dampness left behind by towe one. You will be amazed how much easier this makes drying.
12) Now, if your waxing or sealing, do it.
13) Dress trim while wax/sealant is hazing, also dress wheel wells, tires, dry wheels, polish chrome, and clean door jambs.
14) If you're using a spray wax/sealant for maintenance (highly recommended) then go from step 11 to this step and spray seal/wax, then do #13.