Determine if your invention meets the legal standards for "novelty." Under U.S. law, your invention will be considered novel if you invented it first. To make this determination, decide what features of your invention lead you to believe it is unique, and search for "prior art" or previously issued patents on the website of the U.S. Patent and Trademark Office (USPTO) (see References section).
Determine if your invention meets the legal standards for "utility." If your invention would be considered useful by an engineer, and if it is actually capable of performing its intended purpose, it probably possesses utility for the purposes of patent law. The reason for the requirement of utility is to exclude scientific theories and abstract ideas from eligibility.
Determine if your invention meets the legal standards for "nonobviousness." For your invention to be patentable, it must incorporate some sort of "inventive leap"---an "a-ha!" moment, so to speak. A good test for nonobviousness is to ask yourself if the average specialist in the field to which your patent belongs would find the innovation that constitutes your invention to be the obvious next step. If so, then your invention probably cannot be patented.
Prepare a complete and detailed description of your invention, including graphs, diagrams, drawings and charts---all information and specifications that would be necessary for a manufacturer to build a working prototype. Include specific descriptions in support of your invention's novelty, utility and nonobviousness. This step will require the assistance of an experienced patent attorney.
Apply for registration of your patent with the USPTO using the documentation you prepared in step 4. Much of the application can be submitted online. You will also have to pay a filing fee that varies according to the specific facts of your application and submit a sworn declaration of the truth of your application.
Answer follow-up requests and objections from the USPTO. This is a back-and-forth process that will require the assistance of a patent attorney and normally takes anywhere from several weeks to several months.You should fully understand the relationship between your invention's unique features and the legal standards for novelty, utility and nonobviousness.
Wait for the USPTO to publish the details of your invention. This should take about 18 months after the date you file your patent application. At some later point, the USPTO will approve the patent with effectiveness that will be retroactive to the date of publication. Until then, the status will be "patent pending," which should be enough to deter copycats.