One night, let's say a couple of months ago, you woke up sweating and scribbled something on the copy of yesterday's paper sitting next to your bed, only to fall back asleep. When you woke up in the morning, you had two surprises—one, you could actually read what you wrote the night before, and two, it was a really good idea for a brand-new invention!
Now, flash-forward to today. You've spent every waking moment of the past two months fleshing out your invention. You've figured out what it really is, what it does, how to make it and you're ready to start talking to people about getting it tested and on the market.
Now is the time for you to file a provisional application for patent.
A provisional application for patent is a great first step towards protecting your invention. It basically holds your place in line with the U.S. Patent and Trademark Office (USPTO) for a patent on your invention while you put the finishing touches on your piece of brilliance and work up a full, non-provisional utility patent application. The day you file your provisional application is your filing date, and, as long as you file your corresponding non-provisional application for the same invention within 12 months of your provisional application date and your patent is granted, your invention is protected as of your provisional filing date. That means you get a full 12 extra months of patent protection, backdated to that first filing date! You also get to label your invention “patent pending” as soon as you've filed your provisional application, putting would-be infringers on notice and garnering status for your invention.
So what do you need to do to submit the best possible provisional application and get the most out of it?
Before you even begin: Have a patent search run on your invention. Hire someone reputable to do this for you—a good search will turn up any inventions that may be currently patented and might make your invention unpatentable, and will also turn up past inventions that could have the same effect. In either case, the inventions that you'll be looking for are called “prior art” and the effect that prior art has on inventions, when it's too close to them, is that it renders the would-be new inventions “obvious.” Obvious inventions are not patentable. You want to know about prior art early, so you don't invest too much time and money into something that will later be deemed obvious.
Then, first and foremost: Do not think of your provisional application as something that should be rushed, dashed out, without any eye to its quality. It holds your place in line, but it only holds your place for what is in that provisional application. There is a common misconception that provisional applications are never read or reviewed—they are: when you submit your corresponding non-provisional application and try to take advantage of that early filing date. So, be detailed. Be clear. Provide the USPTO with everything it needs to understand your invention from the start, and everything it will need to be sure that the invention contained in your provisional application is the same as the one you submit sometime in the next 12 months in order to take advantage of that early filing date. Put as much thought into your provisional application as you did into your invention, or have someone reputable put your provisional application together with your input or at your direction.
Second: Know what the USPTO wants. Know the language that that office prefers in patent applications. For example, your title should read something like this: “A device for transportation of humans between various floors in a building.” (That would be an equally fine description for an elevator or an escalator.) Your title should not say “It's a hat” or “I've invented a new way to move people up and down buildings.” Use the language the office knows and loves—it will make it easier for your examiner to read your application when the time comes, and easier for the examiner is better for you. Also, never use your brand name in your application—not in your title (“The Zug-Zwang!”), not anywhere. Your brand name may be amazing and powerful, but it has nothing to do with the function of your invention—and that function is what the USPTO cares about.
Third: Tell the USPTO everything it needs to know. It needs to know how someone skilled in the field of your invention would make and use your invention. This is called the “enablement requirement” and if you don't satisfy that, your application will not hold your place in line. If your non-provisional application does not satisfy that, you will not be granted a patent. Needless to say, this is an important part of any patent application. The reason for this is that a patent is a quid-pro-quo: in exchange for a 20-year monopoly (21, with your provisional term!) on your invention, you must disclose to the public how to make and use that invention so that, when your patent term expires, they can do just that. Think of how expensive drugs become inexpensive generics as soon as the originals' patents expire and you'll have an idea of how this works.
Fourth: Tell the USPTO the best version of your invention. This is called the “best mode.” The best mode is the best one that is known to you at the time of your application. This does not mean the only way your invention can be made or used—just the one you think is best. You cannot withhold the best mode for the same reason that you must disclose how to make and use your invention—the public gets something of value in exchange for your monopoly. But don't limit yourself to the best mode. Describe variations on your invention that you can imagine—substitutions of different materials, different compositions or schematics, or even different uses. Make your invention as potentially broad as possible, while being sure to stay within the bounds of the invention itself. (If you clearly step outside these bounds in a non-provisional application, an examiner will force you to cut those parts out of your application, so it's best to be equally reasonable in your provisional application.)
Fifth, and to continue on the above point: Do not limit your invention to one or a very few iterations, and do not ever say that you “claim” something in your provisional application. Claims are the defined boundaries of your invention—defined by you—and once you set out your claims, your application will be limited to what is within those claims. Better, then, to leave claims completely out of your provisional application (where they are not required) and save them for your non-provisional application when the time comes, and when you are more sure about what exactly your invention entails, and how broad you believe your claims can be.
Finally: Look at your application. Could you understand it if you hadn't invented the invention it contains? Does it need drawings to be understood? If it does, get those drawings together: either make them yourself, or have a professional patent illustrator use your drawings as a basis for professional drawings—this will be money well-spent and will show your application to its best advantage.