Trade secrets are a form of intellectual property protected by state law. Copyrights, patents and trademarks are all protected by federal law. But most states have enacted the Uniform Trade Secrets Act, which provides a nearly de facto form of national trade secret protection. A trade secret is information that provides actual or potential economic value from not being generally known or easily discovered, and is subject to reasonable efforts to maintain its secrecy (under the circumstances).
The determination of whether information is a trade secret is not determined until it is contested. So, you would not know if you have a trade secret until the matter is contested at trial. Theoretically, one could file for declaratory judgment to determine whether the information is protectable as a trade secret, but that would be incredibly wasteful. It would resolve nothing, because a new inquiry into secrecy efforts would need to be done in a later trial.
If you think you have a trade secret, keep it secret. Do not allow people to access to the information unless they need it. Do not post the information for the general public to see it. If you keep it in a desk drawer, lock the drawer. Every little thing you do or do not do in protecting an alleged trade secret is important in determining whether it qualifies as a "trade secret" in the legal sense.