I would avoid the penny on the front sight dry fire advice. You need to learn how to press the trigger at speed and not move the gun, which is likely not what you will be doing (pressing the trigger fast) if you stick a penny on it. Check this drill out:
Taken from another thread on here, do this drill over and over again both dry and live fire: https://pistol-forum.com/showthread....rk-The-Trigger