What to learn?

Hi everyone,

On 11th November 2015, I installed Ubuntu 14.04.3 LTS (Trusty Tahr) on an old Dell Latitude D610 laptop using a 2 GHz Intel Pentium processor, 1016 MB RAM and Intel® 915GM x86/MMX/SSE2 GPU with a 77.6 GB HDD. My dad says it's too old a machine to be productive, but it's been pretty good so far.

Anyway, I am a web design student and found myself drawn to Ubuntu. I am using a borrowed textbook entitled 'Unix in a Nutshell: 4th Edition' that is helping me so far when it comes to some of the shell commands, and have downloaded QT Creator which I have yet to use, but wanted to know what else you would recommend I lea in order to become a more efficient / knowledgeable Ubuntu user, or any resources that you would recommend?

Due to my working / college hours, I have limited time at home in which to lea, so ideally wish to pursue interesting multi-part projects that I can engage with over a period of time - although I can, at a squeeze, make time if I need to.

I am using Gedit to practice some basic HTML, CSS and JavaScript at the moment, but I think I may be more interested in programming languages like C++ and Python. I would also like to contribute to open-source projects at some point.

Let me know what your thoughts are. I am open to critique / advice.