How to adjust the brakes on a bike for optimal performance?

To adjust the brakes on a bike for optimal performance, start by loosening the brake cable tension using the barrel adjuster. Then, adjust the brake pads so they are aligned with the rim and not touching the tire. Test the brakes by squeezing the brake lever to ensure they engage smoothly and stop the bike effectively. Fine-tune the adjustments as needed until the brakes are working properly.