In my approximately five years of professional IT experience (a weird mix of QA, Dev, DevOps) I had the honour of looking at CVs, reviewing candidates and teaching or guiding more junior team members. Let's say my "mentoring" started three years ago.
In these three years, I have seen a lot of people, both my teammates, colleagues and others, like open-source participants, make the same fundamental mistake. This mistake is something which even the wise Vesemir told us not to do. He said: "Don't train alone; it only embeds your errors."
This might sound funny. Taking quotes from fictional characters, but it is something that I think is crucial. I have many times seen starting programmers learn something wrongly and burn it into their mind and then spread the harmful code like a disease everywhere in the codebase.
I want to emphasize that I don't think this is their mistake. Internet is big, dark and full of errors. They are trying, they are learning alone, and they should be praised and encouraged. But they should also start with peer reviewing as soon as possible. This is the "cure" of sorts. Internet is also full of beginning programmers, and not everyone is lucky enough to get a mentor. What I am saying is do things together as soon as possible. Work together but try to learn separately. This will allow all of you to learn new things, share knowledge and discuss better ways, not allowing you to get comfortable with what you know and lowering the risk of embedding wrong ideas into your daily routine.
Now how to find a place where you could code and someone will review your code for free? Github is a start. You can explore repositories; there is a button for it on the main page. You can filter by topics and languages. Pick a smaller project, look through the issues, play with it a bit. Smaller projects tend to be more open to newcomers. Not only do you learn, build meaningful things, but it will also show on your CV.
Good luck and Happy Coding!