We have a male cat who would meow EVERY MORNING sometime between 2 and 4 am. We tried many kinds of discipline, but it didn't stop until one morning I chased him into hiding downstairs and it hasn't happened since. Every morning after for about a week I would go out of my way to thank him and give him attention.
I know many out there would say that running after him was cruel but it worked and he's still as friendly as can be, and we get to sleep through each night.