New vehicles certainly have less chrome, alloy, and various external metal surfaces than old cars do. That said, there's still plenty of cars with chrome detail trim and brushed alloy surfaces, not to mention (often expensive alloy wheels). For the purposes of photography check out the nasty chrome bumper on the 1958 Volkswagen Beetle above. It's not pretty no matter which angle you look at it from. A little bit of elbow grease, and some Meguiars metal polish though, and look at the shine we managed to get back in a few short minutes. Obviously, we'd need to go to work for a bit longer to get that old bumper gleaming like it used to, but a few short minutes shows what is possible.
Metal maintenance isn't especially technical, it just requires some common sense and a little hard work. I've photographed some of my favourite products here, but most of the major manufacturers have a range of different products that you can use to either maintain the shine your metal surfaces once had - or get it back.
Meguiars and Mothers are the two brands that I go to most frequently for my exterior detailing needs and their alloy wheel cleaners and polishes are excellent. The first and most important rule to stick to is to ensure that the surface you are cleaning is free of dirt and grime. You don't want anything that can scratch more delicate surfaces like alloy still lurking when the time comes to clean and polish.
Use a soft, lint free cloth, and don't go overboard with product either. Generally speaking, you should start with a small area, and work to a bigger area once you've got a feel for the pressure and amount of cleaner/polisher required. Most major brands have DIY tutorials on their websites too, some with videos illustrating the best way to use their products.
Probably the smartest piece of advice you could ever take heed of is that it's easier to keep metal surfaces clean from the get go, and keep them that way, than it is to do a once yearly clean. It's a lot easier to keep a metal surface clean than it is to try to clean it from the state that old bumper bar was in.
You'll find too, that products recommended for my delicate surfaces like machines alloy, will be cream based, and usually without an abrasive additive. It might take longer to get the result you want with a product like that, but there's a reason for it, so persevere. Many modern cars will also benefit from various products designed to minimise scratches and scoring on plastic surfaces too. One product I've used to work on plastic headlight covers and plastic convertible windows is Meguiars Scratch X.
Lastly, don't be afraid to have a go. If you use some common sense, and follow the instructions, there's very little chance you'll damage anything.