Correct posture & finger placement
Progress stops when you're fighting your own body, so set up the basics first: feet flat on the floor, elbows bent at roughly 90° by your side, wrists neutral (not resting on the desk or keyboard deck) and eyes looking straight at the screen, not down at your hands.
Fingers should rest lightly on the ASDF JKL; home row with index fingers on the F and J nubs. Every key is assigned to a specific finger — resist the urge to "help" with a stronger finger (for example, reaching C with your left middle instead of left index). Muscle memory builds fastest when the mapping is consistent.