The Wiki is a good place to start, if you what you're looking for. TMO and its list of recent posts is a good place to browse - watching others ask and answer questions - then chip in where you can.
Also, it might be an idea to start doing things through the terminal? Sometimes instead of the equivalent GUI, sometimes because it's the only way to get things done. This device (N900) is my first adventure with Linux, nonetheless using the terminal has allowed me to see how it works (both terminal and device). After a while the commands seep into one's memory without having to look them up each time - though I think you've had a go with apt-get?
Good luck...