Getting your car to look good is all about the method as much as it is the products.. The guys above have already linked you to some awesome products, but I understand your compulsion to try the OTC (over the counter) products first. A few points:
The water spots you are referring to could be from several things, so you kinda need to identify what's causing them (eventually anyway), my guess would be "hard water".
To understand how to remove these waterspots and proceed to making the paint shiny and mirror-like, first lets understand what the paint is. Your paint on your truck (from factory) is actually layers of primer/paint/clearcoat. The primer is the base for the paint to stick to. The paint is the color itself and the clearcoat is actually a thin layer of clear paint on top of your color. The clearcoat is what you are working with, it's smoothness dictates the shine and gloss (assuming the color was sprayed on right).. Remember, if your truck has been repainted then this info won't be completely accurate.
Waterspots can either be pools of minerals from the dried water that have bonded onto the surface of the clearcoat when the water dried, or they can actually be etched into that clearcoat of paint.
The clay bar will take care of this if its the first type (bonded on the paint). This is the least aggressive method, so this should be tried first. There are different grades of detailing clay, so you'd wanna start with a mild clay. The more aggressive clay will tend to leave small scratches in the paint, which means more steps and may not be necessary. Best practices dictates that any time you use an aggressive clay you should follow with a polish to remove any minor imperfections left by the paint.
If its the second type of water spot, no amount of clay will fix it. These spots are actually etched down into the clear paint, and the only way to get them to go away is to shave the surface of the clear coat down to the lowest level of the etching, this involves using a "compound" either a massive amount of hand work, or a cool lil machine to slowly save away very minute (1/100th) layers of that clear coat down until its completely smooth and level.
Before we go any further, you really need to ask yourself.. Do I really need this level of perfection in my paint?
If the answer to that is no, then I say live with the water spots. Otherwise you are opening a Pandora's box that will only cost you money and change the way you see paint jobs.
Go back and read that last two paragraphs carefully, it's important to your wallet as well as your sanity.
Np. here is the link to their site great products and service. 
