Here is what I do: ( Though I can not take credit for this write-up)
Please also note that there is some debate about whether you should wash the wheels first or last.
I recommend 3M's General purpose adhesive cleaner. It will help you safely remove the tar. Scrubbing tar spots is NOT recommended. You'll end up removing some tar and putting it on your wash mit. Then this tar will be rubbed back and forth over your paint causing an even bigger problem.
I highly recommend washing your car yourself. Here are some tips:
Wash the wheels, tires, and wheel wells first. You'll probably need two 100% cotton chenille wash mits to accomplish this. Do the wheels first so that when you rise them off, you're not splatering dirty water all over clean body panels. Do NOT use these wash mits on the rest of the car! I do not recommend any "spray on" wheel cleaners. (If you can wash your vehicle enough, you can render spray on cleaners useless because the less harsh car wash solution will do the trick.)
Buy some Pinnacle microfiber wash mits from AutoGeek. You can do the car with one, but I recommend using three (one for the top surfaces, one for the front and one side, and one for the rear and the other side). I actually own several because I often wash both cars and I don't re-use the mits until I wash them in the washing machine. These mits will minimize the amount of dirt that is swept across the surface of the paint, creating scratches. The web site to buy them from is:http://www.autogeek.net/pinmicmit.html
Use a good quality car wash that does not strip wax. (Car wash will strip wax if you use enough, even if it is of the highest quality. Make sure to dillute it properly with water.)
Use three buckets. Fill the first with plain water to rinse off the dirty mit. Fill the next one with soapy water to wash the dirty mit. Fill the third with soapy water to prime the mit for the next usage.
Wash your car in the shade.
When you wash, use motions from the front to the back (and vice versa). Do not use circular or side to side motions. Do not wipe the same surface over again. This only drags the dirt picked up by the mit over the surface again.
After you clean half a panel, turn the mit over and clean the other half. After each panel, go through the three buckets to completely clean and re-prime the mit. Rinse immediately after each panel so the soap does not dry on your car.
If any spots are left over after you wipe them (such as a dead bug), leave them there. After you dry the car, clean these spots separately with some quick detailer and a microfiber cloth. (This perhaps I don't agree with. To me, the washing environment is more safe because you are using lots of soap suds and water. There is less chance of scratching, especially if you use some water pressure.)
Wash the lowest surfaces on the car last (such as below the facia, under the bumper, and under the side skirts). These are usually filty and fill the mit with dirt that could scratch more visible places on your car. (A lot of people use a completely different mitt because of the dirt)
Use the "perfect drying technique" described on the Autopia website.http://www.autopia.org/forums/showth...&threadid=5120
Some use a high-powered leaf blower to move most of the water off the car. This works well, but you need to be careful not to over use it and create water spots. A California water blade can also be used to help you safely remove most of the left over water. (debated, so use at your own risk, good for windows)
Use waffle-weave microfiber towels to dry the remaining water off the car. JT International (888-989-4584) sells great microfiber towels and they're really inexpensive. Blot, do not wipe, the remaining beads of water off the car. Blotting is more effective and helps insure that any dust that has settled on the car isn't wiped across the surface. An air compressor will help you blow out any remaining water in hard to reach areas (such as side mirrors, trim, license plates, door jams, behind chrome lettering, etc.)
I want to reiterate the imporance of using microfiber towels, wash mits, and applicators. I won't let anything else touch my car.
Also, waxing your car frequently will help prevent dirt sticking to your car and ease the removal of rinse water. (Some waxes actually attract dirt, more so than others, but it does make it easier to remove)
For drying technique:
"low-pressure, high volume water is easiest and perfectly sufficient. Take the nozzle off the hose. Let it pour over the top. You will see the water sheet off. Move the hose down to "feed" the sheet as it flows down the car - this will keep the sheet wide and it will carry away more water that way. (i.e., feed the wet part, not the dry part.) This gets rid of about 90% of the water."
Then I follow with my waffle weave microfiber towel and stretch the towel out on the surface. I press it down gently and then lift it off. Presto, dry! You can also take the waffle weave and blot water off the sides. Regular microfiber towels get soaked really fast, but they are great for drying too. Most of the water spots should wipe off. You can use Z-6 spray sparingly for assistance. Spray the towel with a spritz and that should cover a good area. You can even spray it directly to the car for extra power (which is recommended if you don't mind using a little more Z-6).