Learning to reduce your flinch or tightening around the grip is difficult to identify on your own. A flinch usually consists of gripping the firearm tighter at the point of ignition (when the round goes off), but the recoil of the firearm will generally hide a flinch. The solution to this problem is consistent grip pressure on the gun through the firing process, but how do you identify this problem?
Intermixing live and practice rounds is a great way to see what happens with your fundamentals when there is no recoil. It becomes very obvious that there is an issue with your grip if the muzzle takes a sudden dip downward.
If you would like to have a more concise view of where the muzzle is going, adding a laser to your training can show you where and how far the rounds are being pushed off target. Simply attach a laser to your handgun and do the same dummy round drill you performed before. The laser will give you a more distinct view of where your muzzle is pointed at any given time.
This drill is to be performed after you have warmed up at the range. Start by loading your magazine with at a full load of live ammunition and least 1 inert round. Fire a normal drill for what your training. If possible, have a friend or shooting partner watch the laser and/or the firearm to help diagnose what is happening at the moment the round discharges.
Remember that consistency is the solution. If you consistently have a firm grip on the firearm and you get to know how the firearm recoils, you realize that the firearm recoiling is a natural action. No extra effort is required to mitigate the recoil of the firearm, just the firm grip you have already established.