Mastering a song is when you use plugins like compression, equalization, saturation, and limiting to, generally speaking, make your song sound professional. Mastering comes after mixing and it’s the last stage before you release the song.1
Basically, you want your song to sound like you recorded in a professional studio. Your song should be able to sit on a playlist next to the big pop artists and blend in.
But the most important thing about mastering is that it gives you a second opinion . . .
What are the stages of mastering?
The basic stages of mastering include: 1) prepping and fixing the final mix, 2) bouncing the final mix to a WAV file, 3) enhancing the song with EQ, saturation, compression, stereo widening, and even reverb, 4) compress and limit the track to increase the loudness, and 5) compare it to your reference track.