Seek advice on whether to file an application, based on your search results.
Consider filing a provisional application initially.
Have a patent attorney or agent write your application. Doing so will save money in the long run, because fixing a deficient application takes much more time than does writing a good application from scratch.
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Be concise. Avoid extra page fees. Incorporate external documents by reference, if you can.
Minimize claims. One independent claim may be enough. Avoid dependent claims which have no purpose.
Avoid using multiple dependency. Claims which refer back to more than one other claim make examination more difficult and incur extra official fees.
Avoid late fees. File all your papers at once, including the inventor's declaration.
Avoid extension fees. Reply to rejections immediately. Don't wait until near the "due" date to start working on your response. Allow your attorney time to do his work.
Be willing to compromise with the examiner, and to abandon hopeless positions.
As soon as your patent is granted, you should establish who will be responsible for maintenance fee payments and reminders. And make sure the PTO's "fee address" is changed so that the responsible party receives important reminders and notices.