Water Spots...

Where are you washing you car at? In the driveway or at a car wash. Hardwater is the worse at spotting one up. Try washing it later in the eve when the sun goes down and it is cooler. You might also try using a polish over a wax, I have had better luck with that.

are you just using plain ol' water?? tryout that mr.clean autodry, heard good stuff about it. If not, just give it a bath when the sun is setting

As mentioned above, try not to wash the car in the sun and try to wash it in the shade. Wait till later in the afternoon to wash it, this way, the sun is down and the cars surface has time to cool off. Be sure to use a good car wash. I've had lots of luck with Meguiars NXT wash. Also, when washing the car, wash in sections and ALWAYS keep the rest of the car wet. When washing off the car soap, use a full stream of water at lower pressure. This helps the "sheathing" action and allows more of the water to leave the surface at once. When drying the car, nothing beats a good leather chamois. Be sure to ring it out though as it gets full and repeatedly wipe each area until no water can be seen. Another thing to watch out for is trapped water in the hoodscoop, door panels, side scoops, and trunk lid/rear bumper that will leak out unexpectedly.

As for wax, you should use a good quality wax and not some cheap off-brand crap and you should wax your car as it needs it. When freshly waxed, the cars surface should bead and sheath water with ease. Once the water becomes hard to remove from the surface and the surface feels less smooth and glossed, then its time to re-wax.

Try following this provided info. and let us know the results.

i used to have the same problem, until i got the California Dry Blade. It's amazing and works miracles