The best way to contribute is to identify for yourself things that you think are broken, or could be improved, and then propose a patch/pull request.
A couple of ways to identify possible candidates:
- Have you used component, and wished it would do something a little more? or a little different? In open source circles, people often get involved initially by "scratching your own itch" as the saying goes.
- Have you called up the bug tracker for the related project, and seen any bugs that you can create a patch/pull request for?
- Have you checked your favorite package's TODO for things that have already been thought about, but just are not done yet?