It can be tempting to demand an immediate answer, but it may take a while for people to read your question and get back to you. Even in IRC, where it can seem like there are dozens or hundreds of people hanging around, no one may be looking at the channel. Don't get upset if no one responds right away. Instead, try a different method of contact (email instead of IRC, for instance) or find a different project to work on.
In the other hand, it's totally okay to follow up if it's been a while. How long is a while? A few hours is fine for IRC, and a few days or a week is good for issue trackers, mailing lists, or patches. A simple statement like, "Hi, just wanted to bump this up in case people missed it before" should suffice.
When reporting bugs or asking for helping making a contribution, there's certain kinds of information you'll probably be asked for. It's great to have it at the ready!
This info includes:
This is especially true in IRC but often holds on mailing lists, issue trackers as well. Don't cut and paste big blocks of code! Instead, dump everything in a site like pastebin and link from that.
Every project has a different culture. If you find you don't like the culture of the project you're contributing to, you don't have to keep contributing. There are many projects out there, and some of them will be a good fit for you.
(That said, if you are being harrassed or discriminated against, you don't have to leave quietly. There are people - including us! - who will have your back.)