The first step to success is to keybind everything. Yes, everything. From frag grenade to laceration. I know one person that was good when he clicked, but when I convinced him to keybind he became the best jugg tank on our server.
Next, you'll want to make sure you're using your mouse to turn, not your keyboard. Mouse turners can turn around fast, dart around, all that. Keyboard turners take three seconds to turn around. Terrible mobility.
Third, just understand your class as much as you can, as well as build up your situational awareness.