Maintain an inventor's log book, periodically utilizing dates and obtaining witness signatures.
If interested in foreign patent rights, always file a U.S. patent application before disclosing the invention to the public.
Public disclosure of an invention includes such things as publishing articles about the invention, exhibiting the invention at a trade show, and offering to sell the invention.
If a public disclosure or an offer for sale has been made, you must file a patent application within one year of the date of disclosure or offer for sale.
Do not discuss an invention with an outside party without first having a confidentiality agreement in place with the outside party.
Do not make public and invention before considering whether it should be patented. If an invention is made public before a U.S. patent application is filed, foreign patent protection may be lost.
Remember, when working with independent contractors and suppliers, to obtain signed agreements with them that any patent rights flowing from their work with you will be owned by your company.
Do not forget that you have only one year from the date of first public disclosure or offer for sale of an invention in which to file a U.S. patent application. Furthermore, if interested in foreign patent rights, the U.S. patent application should be filed before public disclosure of the invention.
Do not assume that because your invention is a "minor" improvement over the prior art technology that it is not valuable and that it cannot be patented. Frequently, minor improvements are both patentable and valuable.