So I am not the best/most experienced gamer around; new at it actually. but what I have learned about using the shield is increasing.
1.) You do not have to run to use it. Try lifting your finger off the W to see what happens, then put your finger on the W again. This will help you make sharp corners and throw off the timing of the enemy.
2.) Try to Blitz more than one enemy at a time if you have a teammate to shoot them. Communicate.
3.) Do not try to Blitz more than one enemy at a time if they are not close together. Too much recovery time can be a bad thing.
4.) Low health and Blitz do not go together, bad combination. I only try this as a last ditch effort. It takes too long to drop your shield and start firing, you may take rounds.
5.) Keep your enemy in front of your shield, it is all you have during a Blitz. It is protecting you. Check your flanks as best as possible before your Blitz.
6.) My opinion, using the Blitz to get on point first is a waste. All of the enemy is looking at you waiting for you to drop your shield. You just became a meat-shield. It does not help your team or you.
7.) In my opinion, when a grenade is thrown at you turn your back (shield) to the grenade. It seems to help.
All I got for now.