Build a clean baseline
Take a normal 60-second test without chasing a record. Keep your hands relaxed, look at the target rather than the keyboard when practical, and correct errors normally.
Review corrected and uncorrected errors separately. An uncorrected error changes final output; a corrected error still reveals a movement that broke rhythm.
Practice the transition, not only the letter
Letters rarely appear alone. If R is weak, useful pairs such as er, re, or tr may explain more than the letter by itself. Practice common words and short readable sentences containing those transitions.
Start with familiar words, then add longer words and punctuation. Progressive complexity lets accuracy stabilize before the motion is placed under more pressure.
Retest without overtraining
After a short focused drill, take one comparable benchmark. Enough new attempts are required before a before-versus-after percentage is meaningful.
Stop when tension rises or mistakes become chaotic. Several calm ten-minute sessions usually teach more than one long session built around fatigue.