My sixpence worth...or dimes worth for you Yanks.. I have been `detailing` cars for years..
Only use cold water to wash your car, as hot will strip your wax off. !!
Wash often, i use a mixture of mitts, for the main body, soft brushes for the wheels
and microfibre cloths and chamois for finishing...After getting rid of the excess water with an Autoglym blade Don't mix your cloths, keep the ones you use on your wheels separate
The detailing sprays or no water branded washes are ok for very lightly soiled cars
otherwise you will rub grit into your paintwork
BUT MY BEST ADVISE is to firstly get your paintwork de contaminated and glass smooth with the use of some claybar and work up from there.
If you haven't claybarred your car before...then you are in for a treat!!... Just do it, you WILL be amazed..!! Meguairs do a kit over here for around £20 British pounds...should be alot cheaper over yr side of the pond
There are plenty of downloads showing this on You Tube, some are very long winded.. But shouldn't take u longer than 20 mins for a Boxster...a panel at a time
Make sure you DO NOT DROP the claybar..if u do throw it away..as all the grit will stick to it. Wash the car first of course, and after claybaring finish with a good coat or two of wax.... In all my years have not found anything to beat `Autoglym`
Have fun....and let me know how you get on...you will be amazed