Well, I'm pretty darn good at it, and here's how my thought process works. Basically you just follow the chain and imagine what could be wrong with any link in the chain, then test each of the possible broken links. Start at the most general and then isolate more and more smaller areas in order to first identify where the problem is.
For instance, lets say you open a movie and see it playing, but you hear no audio. Ask yourself "Where's the problem?" Is the problem in this one program, or more systemic? To find out, open another program that makes audio, like playing a youtube video or whatever. If other programs play sound, then the problem is in the first software only. If nothing makes sound come out of your Mac, then the problem is not in any particular piece of software, so you don't need to check any of the settings in any programs.
Then you ask the next most general question, "is the problem inside the computer, or outside the computer?" So you unplug your speakers from the headphone jack and stick in the plug to your earbuds, then see if you hear sound. If you hear sound in your earbuds, then something was wrong with your speakers. If you don't hear sounds then the problem is somewhere between when the software tells the computer to output some sound, and the point where sound actually is sent out of the headphone jack.
And so on and so forth. Just start from the most general areas you can isolate to see if the problem is in big part A or big part B. Then just keep isolating smaller and smaller parts until you've found the broken link in the chain.
It takes a decent amount of technical knowledge, but that comes with experience. If the topic of computers is interesting to you then you won't really have to go out on a mission to learn the technical details, you'll just pick them up as you explore your hobby.
