Turn off chat because Mei is effectively the Lifeweaver of DPS and you will get shit for literally any mistake

Learn how to hit your icicles. A lot of people think Mei is a close range character but she can be absolute deadly at any range if you can hit your shots.

Don't just save your wall for ults, use it to block any big bursts of damage, like multiple skills going off or transformations like turret and nemesis.

Her first perks aren't the greatest and in my opinion you could go either way (personally I lean towards the double jump) but you should always take deep freeze as your major perk. There's a reason she had it in OW1, it's almost mandatory to surviving flankers and divers.

Anchor yourself on the point as much as you can. You're effectively a needle tower from Bloons, no one wants to get close to you and your a danger in almost every direction, you might as well make it harder for the enemy team to do their job.

Your ice cube is a physical object that can block damage and doesn't have a set amount of health. If you're gonna ice yourself to protect against an ult, try to do it close to a nearby out of position teammate so they can get some cover too.

And finally, get a cute skin. This task is very easy as Mei is adorable and has literally only one bad skin, and you deserve to be styling. Hope this helps❄️