How do I know that someone is Moshiach? Will I just know? Are there requirements? If someone tells me that he is the Moshiach, is he to be believed. It would seem seem strange to say so.
Here are the Rambam's instructions on how to recognize Moshiach: Melachim U'Milchamotahem 11
A Jewish King from the House of David who learns and observes the Torah (written and oral) and assures that Israel does as well can be presumed to be Moshiach.
If he does so and rebuilds the Beis HaMikdosh and gathers in the exiles he certainly is Moshiach.