1. use it often :-)
2. write a module review for perlmonks
3. write some code using the module and post it
4. talk about points 1, 2 and 3 as often as you can
5. and don't waste module authors time with saying "hello", they will be happier when the get a bug report or even the fix for that bug, but search for his web-page on CPAN or even talk about the module in other places (e.g. use.perl.com)