If you're locking your brakes up there are a few potential problems. 1) something is wrong with your brake system that makes it too sensitive and locks the brakes easily. 2) You're a bad driver and are locking the brakes up when you shouldn't be. 3) You have really bad tires and need to upgrade them(this goes along with number 2 though, if you know how to drive it shouldn't matter).
If the problem is your driving, upgrading your brakes will make this problem even worse. If something is wrong with your brakes, fix it. If your tires are bad, get better ones. If you're the one locking them up, stop locking them up...