Here's something to make your wheels/tires, and over-all vehicle look better:
Use a heavier duty degreaser/cleaner to clean out your wheel wells. Yes, yes, I know, isn't that going just a little too far? It really does make a definite difference in appearance.
Just look around your wheels after a wash, and what do you see? Sort of a grungy, pale, non inviting appearance.
What do you see when you look at a brand new car? A dark, almost black area where the chrome/aluminum wheel really sticks out.
In other words, the wheel well is sort of the frame that surrounds the wheel. If the frame doesn't look good, the picture won't look as good as it should. See what I mean?
I have found that Meguiars "EXTRA All Surface Cleaner" does a FABULOUS job at this. Just spray it on, let it sit for a moment, and spray it off. It's absolutely incredible how good a job it does! You might need to use a small scrub brush the first time in order to get the thicker tar, but after that first time it gets a lot easier. The result is a beautifully clean and dark colored wheel well area.
Here's a link to Meguiar's web site where this stuff is detailed: