I've installed Linux and I've done a lot on it so far and I'm currently looking for another project to keep myself busy while working on it. Any suggestions that I can try/do? I would say I'm at the intermediate level.
Configure some virtual machines?
Practice with some servers?
Hook up stuff! That has always worked for me. Roll out your own cloud, your own mail server, you own SIP communication network, your own NAS, your own print server. Make some custom software that could help you at work or at home or in school. Hook up your phone, roll out a few web-based services for your friends or family or colleagues or commilitones.
Do you have an IDE on your machine? Have you done some development?
IDK What your progress level is, but everyone should set up and run a brief web server at some point, even if you're just learning the basics with LAMP and pop like WordPress or something on there...
I have a 24/7 file server, web server, ftp server, and a print server. I also have done a lot with my Pis that I have set up. The email server does sound like fun. I actually have a lot of websites currently. @Zoltan, unsure what you mean by development. Like make my own Distro or edit one?
I think Zoltan meant "Have you done any sort of Software development"
Just what do you like, would you like to make your own applications or get involved in an open source software project? Do you have any experience with IDE's? Hacking around with linux distros is not really software development, it's a lot of fun, without having to know C or other languages, depending on how deep you want to get into the stuff and what you want to achieve. It's perfectly possible to optimize custom linux distros for instance, without knowing C, and you can get some really great results with that.
I have done some software development. Not much as I don't really have that sort of mindset of finding a problem and using a program to solve it. I do like automating things with shell scripts though. I did find a project for me to do that I'm currently working on.
Break it.
Google the error code and fix it.
Then break it again. Rinse repeat.
Then really break that joker. I mean really get in there and mess with it. And fix it.
If you want to give back to the community pick a project you like and help them, report bugs or if you can fix bugs and submit patches. Help with translations if you know several languages, go on forums or IRC and help users.
If you want something more personal try and install Linux from Scratch, it's kind of rolling your own distro, you get to pick everything and end up with a working linux where you maintain every aspect.
Baby steps: Install Gentoo or a source based distro, compile your kernel for your hardware specifically instead of using genkernel on gentoo or similar tools, control every aspect of your system, maintain that distribution across major kernel releases or X releases without breakage.
Survive an emerge -e on gentoo..