some cheap basics:
If you have time, hand wash the car every 3-5 days, weather permitting. First hose the car down including all wheels, do not wash the car in hot sunlight, Put a capful of Meguiar's gold car wash in the bucket. Apply with a clean supple soft sponge, rinse off with a garden hose. Dry with a microfiber towel, not terrycloth.
And clean the wheels each time you get gas. 5-7 extra minutes, dip a few paper towels, into the gas pump's squeegee box, soak 'em and give the wheels, at least the front ones, a quick clean, it helps keep the brake dust from getting built up and baked on.
Spritz a little Simple Green once a month on the engine, and the nooks and crannies, after cleaning out the leaves and gunk in front of the windshield and the battery tray, where a lot gets in, to keep it clean, then clean it off with a sopping wet rag; wearing disposable gloves, about once a month apply Nev-R-Dull to the airbox lid, it will really shine up well.
Leatherique is the best leather treatmentout there,, q-tips between the air vent registers, and a shop vac to keep the carpets clean, and dash protectant other than armorall for the dashboard and door materials.
Sprayway glass cleaner is used by detailers for the windows.
I hand wax. Many wax choices are good.
Every year is touch up paint time, i use the Mercedes Benz factory paint pin from the dealer for that.
Mothers back to black for the exterior rubber bits works ok.
I think the most important single thing is to wash the car as often as you can though.