Understanding recording means having a basic idea about microphone placement and room acoustics, input and output levels, compression, getting sound into a computer, using outboard gear and knowing how to choose soundcards and audio interfaces.
Mixing is the art of making sure every instrument is heard in its proper space. How you mix depends on whether you're working with vocal music, guitar-heavy songs or tracks that feature heavy bass and drums. It's important to know what you want--and how to achieve it--with a mixing board, software, headphones and monitors.
This is where knowledge of your DAW (digital audio workstation) and your software comes in handy. Editing can involve cutting and pruning as necessary, creating a perfect track from several takes, looking at tracks with a magnifying glass and cleaning up even the tiniest imperfections.
There's an art to pulling the best work from co-workers or clients, knowing when to push, when to do just one more take and when to let it rest for a few hours. Knowing even a little about arranging, music theory, engineering and songwriting can help you communicate with the other musicians, too.
In the modern studio, it's imperative to know at least a little bit about MIDI, synthesis and how to tweak synthesizer, keyboard and drum machine sounds. Since everyone's using the same gear, the onus is on you to make something original--something truly "you"--from the same presets.
For many artists, "making beats" involves the entire process of recording, mixing, editing, producing and programming. For others, making a beat means putting together the rhythm tracks--the bass, drum and percussive elements. Either way, it involves getting creative, trying new techniques and knowing your gear inside and out.
Mastering is usually the last step in the production process. It's crucial to know how to use mastering tools to give your product an overall, consistent sheen. If you get your music mastered by a pro, it's still important to know what to do before you send it out---and what to listen for when it comes back.