I like to break all products up into 3 categories. Botique, Over the counter, and Bulk. Botiques have the best quality but are expensive, OTC has a mix of good to horrible, and Bulk is mostly average and sold in 5 gal jugs. Botiques brands are P21S, Poorboys, 4 star, Sonus, etc. OTC are Meguiars, Eagle One, Mothers, etc. Bulk is Auto Magic, PRO, Car Brite, Meguiars has a bulk line, etc. Accessability wise, OTC products are usually at any auto store/wal mart. For OTC products, try to stick with the bigger names. Eagle One/Mothers/Meguiars all make excellent OTC soaps that are reasonably priced.
Regardless of the soap used, if you use a dirty mitt/drying towel you're going to put swirls in your paint. I like to use Chenelle mitts and Microfiber drying towels. I use Meguiar's Gold Class mitts and Meguiar's water magnet drying towel. Regardless of what you use, try to stay way from sponges.
When you wash, use 2 buckets. One for soap, one for rinse. After every panel, rinse your mitt out. This gets all the dirt out of the mitt so it won't be dragged across the panel.
When drying, try patting the panels dry instead of dragging the towel across it.
For interior cleaning, if you want a 100% grease mark free finish, try some Meguiar's Interior Quik Detailer. It doesn't darken the dash. If you want something that will darken your dash try Mothers, Lexol, or Meguiar's protectant. Meg's NXT is greasy so stay away from that. Apply it with a cotton wax applicator and wipe it down with a microfiber after about 15 min.
Carpets can be taken care of with any household carpet cleaner. Resolve is EXCELLENT. I use Meguiar's All Purpose Cleaner for carpets. It's a bulk product so it can't be purchased OTC. I haven't really used anything else on carpets so I can't comment on how good others are. In the past year a lot of dedicated OTC carpet cleaners have come on the market and it's one of the few things I haven't tried.
The best way to clean your carpets is not to get them dirty in the first place. Vacuum every week, don't eat/drink (water is ok) in your car, and get a good set of rubber floor mats. The carpets in my Mom's Taurus look brand new (as well as everything else in the car) and it's a 98 with 90k on it.
For leather I REALLY like Lexol. They make a cleaner and conditioner and it's about all I use on leather. I also have an unlimited free supply of it!! :banana:
Any other questions? I've detailed cars since before I could drive.....damn 13 years.....If it's out there, I've used it. But, what you'll find out is it's not what you use but how you use it.