First - Start With The Wheels!
You can normally tell a pro detailer by two things at first glance: 1. they have two or more buckets, and 2. they start with the wheels first. So that's where we are going to start - the wheels.
Why? Because while most of us growing up were taught to clean the wheels last as the water gets dirty, you risk rinsing brake dust onto the clean paint around the wheels if you do them last, you are better to wash the wheels first, then get clean water and wash the rest of the car. Or have a dedicated wheel bucket the sign of a true pro.
Video: How to clean the dirtiest wheels:
The main reason a lot of people find cleaning wheels slow and difficult is that they don’t have a range of brushes, they try and clean the whole wheel with the same brush or mitt, and just can’t get in all the different areas.
You really need a range of brushes to clean all of the wheel quickly and properly, as no one brush will get everywhere properly, and mucking around trying without the right range just wastes time and gets poor results.
A soft flat brush for the flat surfaces or the wheel is quick, but you can't reach in the wheel barrel properly, or around the wheel nuts. You can use this on the tyres but a stiffer brush will scrub them better, but a stiffer brush could scratch the mag wheels so you only want to use that on the rubber.
A long brush that can fit in those tight gaps between the wheel spokes and in and around calipers is perfect for cleaning between the spokes and the barrel of the wheel, but you can’t clean much else with it.
A detailer brush is perfect for around wheel nuts and those little hard to get corners that most people seem to miss (or they do with their finger), but you only use it for that as it would take way too long to do a whole wheel with a small brush like that.
Having the right gear makes it easy. I have all these in a dedicated wheel bucket with a dirt trap in the bottom. I grab the brush I need form the bucket, then drop it back and grab the next brush, it makes it so quick and easy and I do a much better job. I see people all the time spending ages trying to get hard to reach bits on their wheels, all they need is a few more brushes and it would be easy! Brushes last ages so grab a kit with a range and you're all set.
I use normally use Fireball Wheel & Tyre, Autostolz Wheel Cleaner, Sticky wheel gel or diablo as a concentrate, so you need to dilute it in a spray bottle.
I also have Decon on standby, it’s not a cleaner but will break the chemical bond of iron from brake dust so that you can remove it, I only tend to use this when I need to, but its real handy and helps get brake dust that you otherwise can’t remove off. This is really important as if you leave brake dust on it can etch in and pit the mag wheels.
The best thing I've done on my wheels is get them mint and then put Autostolz Enhanced Wax (Actually a sealant), or Max Coat Wheel Sealant on the mags including in the barrel, it makes it so much easier to clean! Well worth it.
If you are in a hurry just cleaning the wheels alone will make your car look a lot better.