For the uninitiated, the lingo and layout of lmms or Ardour3 or other Digital Audio workstations can be very intimidating. I hardly know where to start, nor how to give advice. Thanks to the rise of Dubstep, there are hundreds of very helpful youtube tutorials such as: http://www.youtube.com/watch?v=naQW2RkpfYY. I like this one because it is a nice visual intro to detuning and combing saw-tooth sound waves via an 'oscillator' to make a sound (instrument?) recognizable in, say, Skrillex.
Composing music with a DAW has revolutionized how I listen to songs: I can't help but listen for the subtle signatures of familiar saw-waves or moog-filters or peculiar sounds and then try to recreate them. It feels great, like becoming an active participant rather than just a passive consumer.