Mastering can be broken into 5 stages:
1) Tuning. I always request reference tracks prior to beginning a project so I can “tune” my ears to a particular style and sound. This typically involves a few hours of critical listening.
2) Learning. More critical listening here. I listen to a pre-mastered mix until I thoroughly know every song and its dynamic changes, instrument alterations, transients and equalization concerns.
3) Operation. BY this phase I am 100% sure how I want the master to sound and 80% sure how to accomplish it. During this phase I am experimenting with signal flow through a variety of analog processors. (i.e. Which EQs and where do they go in the signal chain, before or after compression or both? How many and which compressors? How quick are the transients? This experimental phase helps to tailor a signal chain to best suit the sound I’m after.
4) Processing. Process the mix through the signal chain. A lot of notes are taken here as different parts within a song will require custom equalization and dynamic processing. A full length album will take 3-4 days during this process.
5) Finalizing. This is the final listen . I use at least two days and get fresh ears on the material on a variety of systems. Any “tweaks” and alterations are made during this stage. Sometimes returning to the previous step if necessary.