The plaintext is
This is my cipher, This is my song, I'll write like this, All the day long.
the way it works is that each character is (if alphabetic) rotated through the alphabet by a number of places that increases by 1 for each character (whether or not alphabetic).
For what it's worth, I didn't look at the hints, so it's fair to say that the puzzle didn't need them :-).
The thing that made this sort of thing an obvious guess was the T'yz. It's gotta be I'll or I've, and the fact that y and z are adjacent letters was striking.
As a general rule, this sort of cipher puzzle is usually either too easy or too difficult; the more interesting one tend to be ones that would be too difficult except that there's some other information besides the ciphertext that somehow helps with the decryption, preferably integrated with the puzzle rather than provided explicitly in hints. (Or sometimes a fairly easy cipher puzzle is one component of a larger puzzle.)