If you are in the stage where you are still developing the inventions, you can apply for a provisional patent before anyone else does to get the superior rights over a patent.
If you have someone with you in developing the inventions, you can ask him to sign an NDA to prevent him from sharing the inventions to a third party.
Because of the detour justalayman and I took, did you think that godamongmen might have forgotten what was advised in the first several posts of this thread, Lucas?
Applying for a PPA does not give a patent applicant superior rights. When filed, the PPA allows an inventor the right to claim s/he has a patent pending and the PPA allows the inventor the benefit of an earlier filing date than might otherwise be possible. The inventor still needs to file the regular patent application.
Until the patent is actually issued, however, an inventor cannot prevent someone else from making the same invention and marketing it.
A lot can happen between the filing of a provisional patent application and patent approval.
