Get faster: finger tricks, look-ahead and practice

Knowing CFOP is half of it. The rest is turning smoothly and never stopping to search for the next piece.

R U R' U' × 6

Drill: R U R' U' six times, as smoothly as you can

Finger tricks

Turn with your fingers, not your whole hand, and don't let go of the cube between moves.

Hold it with your thumbs on the front face and your fingers on the back.
U: flick the back-right corner of the top layer towards you with your right index finger.
U': flick the back-left corner towards you with your left index finger.
R and R': turn your right wrist. Keep your grip; don't reach round the cube.
F: push the top edge of the front face to the right with your right index finger.

Practise on R U R' U': it should become one smooth motion. If your cube is stiff, a cheap speed cube makes a big difference.

Most of the time in a slow solve is spent looking, not turning.

Turn slower than feels natural, but without stopping. A smooth, slow solve beats a fast one with pauses.
During F2L, while you insert one pair, look for the next one.
Plan the cross with its first F2L pair in mind, so you know where to start.

A good drill: solve with a metronome, one move per beat, and never let a beat pass without a move.

Use a timer. Any cube timer app works. Start with 15 seconds to look at the cube before you start, as in competitions.
Track your average of 5, not your single best. Speedcubers drop the best and worst of five solves and average the other three.
Find your slow step. Time each step for a few solves. For most people it's F2L.

When 2-look OLL and PLL feel automatic:

Full PLL: 21 algorithms. Start with the ones that show up most and take longest with 2 looks.
More F2L: learn to handle each case the shortest way, and to use the back slots without turning the cube.
Full OLL: 57 algorithms. Most people learn it last.
Colour neutrality: start with whichever cross is easiest on each scramble, not always white.

Lost in the middle of an algorithm shows how to recover. Or scan your cube and the solver shows you the moves from where you are.