When I was buying aftermarket wheels for my first car, I learned a few things about buying wheels that I’ll keep in mind the next time I do this.  For instance:

• Consider how easy a finish is to clean.  When choosing what kind of finish you want on your wheels, keep in mind that some finishes are not as easy to clean.  Chrome finishes are the easiest to clean, but also show dirt and smudges more quickly than other finishes.  What you don’t want is a porous finish, as those are difficult to get brake dust and other dirt out of.
• Look at wheels with the correct lug pattern.  Most cars have 5-lug patterns, but not all do.  This can be a challenge if you have a wheel with a really odd lug pattern, like my first car — a 1981 Nissan 280ZX, which has a 4-lug pattern.  What works for BMW wheels or VW wheels might not work for another type of car.  Don’t get your hopes up by looking at wheels that won’t even work on your car.
• Consider how much clearance you have in your wheel well, and how much space you need for your brakes.  Not every wheel is going to work for every car, even if the lug pattern works out.  For instance, if you want Beyern wheels, make sure they’ll leave enough room for the brakes and fit in the wheel wells before you purchase them.

Buying aftermarket wheels for the first time is exciting, but as I learned it can also be confusing until you learn the different things you need to look for.  Do your research before making a purchase, though, and you should be plenty happy with the results!