A patent is simply a legal document that describes your invention and the idea behind your invention. It is essential that you get a qualified patent attroney to help you come up with your patent application. Otherwise you might end up with a legal document that is difficult to enforce because it is vague or imprecise. Patents, and patent applications generally comprise the following sections"
Abstract. This is a short summary of your invention. You would put the key information here so that other people searching through patents can quickly understand the gist of your idea.
Background of the Invention. You would usually describe the problem and current solutions to the problem here. You should be careful not to describe your idea or solution in this section, or it could be considered prior art.
Summary of the Invention. This is where you provide a brief summary of your idea and how it solves the problem.
Figures. This is where you would include drawings and diagrams to illustrate your invention. Patent attorneys will help you draft professional patent drawings, thought it is not unheard of for patents to include hand-drawn drawings. Whichever way you go, the key thing is to ensure that your diagrams explain your idea clearly. A picture as they say, is worth a thousand words. (But that doesn't mean you don't have to write much if your diagrams are very expressive.
Embodiments. This is where you descibe how your invention can be implemented. For example, if your idea is a new type of automotive transmission using electro magnetics, then you describe how you could actually go about constructing such a transmission in this section. One of the objectives of this section is to show that your invention is implementable, and not just a pipe dream.
Claims. This is where you make assert your right to specific ideas in your invention. This is usually the most tricky part to prepare because you want to be sure to claim all the "core ideas" behind your invention. Otherwise you may not be afforded the intellectual property protection that you seek. A good patent attorney and patent engineers will be able to help you draft a good set of claims for your patent. This section is probably the most important part of your patent, and is where the courts will look at to judge if a patent infringement has occured.
You can find examples of patents at the Google Patents (external site) site.