How do I give proper notice to a month to month tenant to vacate an apt in buffalo ny?

Give them one full rental period notice. So if you want them out but 9/30, tell them today or tmmw. Hand them a letter saying:

Please be informed that I am terminating our leasing agreement effective 9/30. Please make arrangement to vacate the premises at <insert address> by that date.

Send it certified and hand them a copy, if practical.