I have been making iOS apps for the last 3 years. To become a better engineer I would like to contribute to an open source project. I am looking for suggestions.
My Coderwall App (https://github.com/OiNutter/Coderwall-iOS) is open source and I'd be happy to have you to take a look and maybe make some suggestions. However it's my first ever app so I doubt it would do much to help you with your goal of becoming an engineer. Even so, if you want to take a look and get involved then feel free.