I put a '=head1 THANKS TO' section in the module documentation that lists all the contributors.

As for how to persuade an author to apply your patch quickly:

• Create the patch against the author's public source code repository if possible, as that may be more up-to-date than what's on the CPAN;
• Use diff -u to create it;
• Include tests that fail without the rest of your patch and pass with it;
• Include documentation if adding or changing functionality;
• Think carefully about whether anything in your patch might affect anything else, and add more tests to prove that it doesn't, thus saving me the effort of doing so.

The patch for the module itself is the smallest of all these! Mind you, even if you do do all of that, don't get upset if it doesn't get applied quickly. Module authors are busy people, with important things to do like making beer, working on their car, trying to create the perfect pie, and so on.