Playing as Reinhardt
There is no point on advancing alone with your shield. Carry some partners who can shoot with you, while some attackers flank from another path.
Reinhardt's shield takes longer to begin recharging if it was destroyed, so try to let it recharge before that happens.
Do be aware of what your friends are up to at all times, because there is very little that's more annoying in Overwatch than to have a Reinhardt go charging off into another section of the map, leaving his previously sheltered friends at the mercy of the enemy!
Zarya is your best friend. Blocking bullets with your barrier while she shields you empowers her shot, and her ult allows you to easily aim your charge for instakills.
As Reinhardt after you use your earth shatter use your fire blast. And then charge into one of the enemies. If they survive the first two this will prolong the stun plus most likely take them out.
Reinhardt's hammer has a rectangular hitbox when swung. If you move your mouse left and right when swinging it will increase the area that your hammer connects with.
Despite popular belief, Reinhardt's shield can be destroyed if it takes too much damage (over 2000), characters like Bastion can easily overwhelm his shield if he and his team position poorly.
If you're on a Payload map, using Reinhardt's shield to protect a Bastion or Torbjorn Turret while riding the objective can be a very powerful play. Just make sure someone's keeping the rear clear while you progress through the map!
It sounds a little obvious to mention but Reinhardt's defining characteristic is his immense shield. Make sure it's up whenever it makes sense to have it in use - even the greenest teammate should get the message and get into position when they see it hum into action.
For a little piece of mind you might consider combo-ing Earthshatter with Charge. That way you can get stuck right into a pack of enemies, then immediately stun them so that your teammates can get on with the job of taking out the trash. Alternatively, drop Earthshatter, and then slam your way into the most important target!
If timed well, you can charge D. Va's mech as it is about to explode, sacrificing yourself, but displacing her ultimate, and maybe even getting close enough to get her killed by the blast.
Reinhardt is a particularly annoying obstalce to Roadhog. His shield will protect the team from his hookshot, and Roadhog moves so slowly that you shouldn't have too much trouble taking a slice off him with Fire Strike
Reinhardt's charge can steer left and right a few degrees at any time. Not only is this good for correcting your charge's aim, but you can steer into obstacles for a quick stop so you're not stuck hurtling into a bad position.
Remember you can always Fire Strike immediately after a melee for a quick animation canceled one-two attack. Great for leveling the playing field with other tanks.
do not use your shiled its a pice of sh*t instead just try to kill the opppents Bastion D.Va Roadhog and Symmetra and if none of your oppents are being that character just go into the battle filed and spam emote
Playing with Reinhardt
GET BEHING THE FU***NG SHIELD !
Pay attention to how the shield looks, if it has a lot of cracks in it then it's in danger of breaking, the Reinhardt may drop the shield at any time to try and let it's health restore. So be prepared to move away from him and get to some other form of cover.
You can shoot through the shield, so if you're pushing stay alongside him.
Watch out because a crappy Reinhardt might shield your whole team one minute then leave you all hanging the next. If not ready for this you will be destroyed by the other team!
Playing against Reinhardt
When Reinhardt charges ahead of his team into the center of your team, that likely means he is planning to use his ultimate, Earthshatter. Spread out until Reinhardt dies or retreats to ensure that he does not Earthshatter multiple people.
Reinhardt is capable of pinning targets against walls and other nearby objects, which is usually more than enough to one shot squishies like Mercy. Always move when you're against Reinhardt!
Symmetra's right-click shot completely ignores Reinhardt's barrier and deals full damage even after passing through it.
Reinhardt is always vulnerable from behind, but so is his team! Offensive characters should attempt to sneak behind Reinhardt and his team where they're least expecting to be attacked from next.
SHOOT THE SHIELD.
Edit: For real. 2000 hp may SEEM daunting, but in a game with unlimited ammo, it's totally not. If you knock down his barrier, it stays down for eight seconds.
Don't hesitate to shoot his shield if you have the time and ammo, since you'll charge your ultimate by damaging it.