The best way to get this feedback, imho (and it worked for me) is to start contributing to an active open source project you use.
Specifically, contribute to one you use, not one you think is cool or would be fun to hack on. If you have to ask "what would be something useful I could work on?" on the mailing list, you're doing it wrong. Look at your use and start implementing something that is missing, awkward, or doesn't work well.
Submit patches with explanations of why you did it the way you did. Assuming it isn't a totally anti-social project, you will get feedback and advice. The key thing is that you are coming to the folks offering something useful to their baby rather than begging ;-)
Specifically, contribute to one you use, not one you think is cool or would be fun to hack on. If you have to ask "what would be something useful I could work on?" on the mailing list, you're doing it wrong. Look at your use and start implementing something that is missing, awkward, or doesn't work well.
Submit patches with explanations of why you did it the way you did. Assuming it isn't a totally anti-social project, you will get feedback and advice. The key thing is that you are coming to the folks offering something useful to their baby rather than begging ;-)