Some of my recommendations:
#1-Wash with two buckets, one for soap and the other for rinse water.
#2-Get a nice sheepskin mitt, soft sponge, or microfiber mitt. I like the sheepskins at Walmart. Look for the softest ones.
#3-Don't scrub hard with anything on the paint or you'll make scratches.
#4-Use a "sheeting" method to rinse the car. That means don't use a nozzle on the hose. You'll find most of the water flows right off the car.
#5-Dry with a soft towel like a microfiber. Shamois are OK, but I've found they rip apart after a while. And when you dry, try to blot, or put very little pressure on the towel. Some even go so far as to dry with a leaf blower.
#6-Use a clay bar at least once a year. Just follow the directions. It will get out contaminants like sap, imbedded dirt, etc.
#7 (if you can afford it)-Buy a polisher like the Porter Cable 7424 or 7336, get some pads and polish. Those will get out what scratches you do have. You can use that a couple times a year with no worries of thinning the paint.
#8-Seal the paint. You can use sealants or waxes. Sealants are usually more durable. The norm is to use two coats at a time, and do it every couple of months. For the best look, most like to use and sealant topped by a wax since wax usually has a better look.
You can find most anything locally. Meguiar'* is good stuff for washing items, towels and wax. Viking also has good towels. The best products are mostly found online. check out www.autogeek.net
Autogeek as well as www.autopia.org
are great forums where you can learn about what polishes to use and what all is out there for detailing.