How can I determine whether my method is cryptographically correct?
Well, that depends quite a bit on what your primitive does, and what security properties you claim for it. As for examples of security properties, you might claim it does privacy (someone without the key cannot determine anything about the plaintext) or integrity (if someone without the key modifies the message, with high probability the decryptor will notice it).
In general, determining whether an encryption method is secure is a hard problem. However, if your method takes a keystream (generated from outside your solution) as long as the message, and combines it somehow to form the encrypted message, and your aim is to provide privacy, it turns out there's it may be easy to show: show that for every pair of plaintexts and ciphertexts of the same length, there exists one possible keystream that would convert that plaintext into that ciphertext (or, more generally, exactly $N$ keystreams, for some fixed $N$ independent of the plaintext/ciphertext). If you can show that, then you've shown that if the attacker cannot distinguish the keystream from random, he cannot gain any information from the ciphertext (because, as far as he can tell, all plaintexts are equally possible); hence you have a secure solution (as long as you use a cryptographically secure keystream generator).
How can I determine whether my method is cryptographically significant?
Well, that's actually fairly easy: with extremely high likelihood, it isn't. If it is just a way to combine a plaintext and a key stream, well, you might be able to show it's secure, but we have existing ways to combine plaintexts and keystreams, and those work quite well. If my guess is wrong, and you've got something else, well, you need to show cryptographically correctness first (and if that involves showing some computational problem is hard, that's extremely difficult to show, even if you got it right, which you probably haven't).
Can I make money thorough this method just by selling it to an encryption company or organization?
Another easy question: no. There are lots of encryption algorithms which are both free and have been vetted by respected cryptographer (the types that have broken other ciphers). Why would anyone pay you anything, when they can get better solutions for free?