Don't dive off the deep end, it's easy to overestimate your time/effort/ambition ... wade in.
The best way to learn about coding, stretch your skills, and help the community is to find something that can use more tests or fixes to existing bugs -- the merit of new features may be disputed, but few people can argue with a bug fix or better test coverage.
go through the phalanx ... look for modules you use that have little problems you think you can fix easily. no matter how trivial they may be, fixing them will involve becoming more familiar with the code involved, which will give you more breadth of perl knowledge. submitting the patches will give you more exposure to the world of "open development" and pave the way for more ambitious projects.