A rock mix is a fight for the 200Hz-3kHz midrange. Distorted guitars, vocals, snare, and toms all live there, and the average rock track has at least two distorted guitars stacked, sometimes four. If you don't carve specific spectral lanes for each element, they pile up and the mix turns into mud where nothing is clearly audible. The single highest-leverage skill in rock mixing is subtractive EQ: cutting frequencies from instruments that don't need them rather than boosting frequencies you want to hear.
The kick-bass relationship is the second pillar. They share the bottom octave (40-120Hz) and need to coexist without phase cancellation or muddiness. The traditional approach is to give each one a "primary territory" via complementary EQ: the kick owns the 60-80Hz thump, the bass owns the 80-150Hz body, and they handshake around 100Hz. A high-pass on everything else above 100Hz keeps the bottom clean and lets the rhythm section drive the track.
Drum compression in rock is more aggressive than in any other genre except metal. The kick gets a fast attack to preserve the click and a medium release to let it breathe. The snare gets parallel compression — a heavily-squashed copy mixed under the dry signal — for thickness without losing the transient. The room mics often get the most aggressive compression of all (4:1 or more, fast attack, fast release) to extract the explosive ambient bloom that makes a rock kit sound bigger than its individual mics.