Search the Prior Art. Finding prior art is not too hard if you know where to look. The most common reason that an examiner or an applicant may miss an important piece of prior art is that they did not know where to look, or they did not have access to the right places. For example, U.S. patent examiners almost always focus their prior art search on the prior art that exists in the U.S. patent database. Because this database is well indexed and organized and is easily accessible to examiners, they concentrate their efforts there.
Examiners also search other databases, but usually only English-language ones.
As a result, they often miss documents that are not indexed in any English language databases. You should focus your prior art search on documents you know that seem relevant to the patented system. The prior art you are looking for can be any printed publication, in any language, that was published before the filing date of the patent. Useful prior art can be a patent, technical specification, owner's manual, user's manual, web page, textbook, business plan, case study, or any other similar printed publication. If you are a student or professor, you should check your school library or library network.