Boruto improves his chakra control throughout the series by training with his mentor, Sasuke Uchiha, who helps him develop various chakra control exercises and techniques. Additionally, Boruto undergoes intense training sessions with his teammates and participates in missions that require precise chakra manipulation, which further enhances his skills over time. Through dedication, perseverance, and guidance from experienced shinobi, Boruto steadily improves his chakra control throughout the series.