Detailed Answer
Common causes: 1) Fingers drift from home row – return to ASDF JKL; after each word. 2) You're reaching with the wrong finger (e.g., using index for 'C' instead of middle finger). 3) Keyboard too small or too large for your hand. 4) Low tactile feedback – try a mechanical keyboard. 5) Looking at the keyboard while typing (you mis-aim because eyes and hands conflict). 6) Fatigue. 7) You're rushing – slow down to 70% speed until you hit the right keys consistently. Use Keybr.com's 'error heatmap' to see which keys you miss most, then drill those pairs.