This is my first guide so please keep the criticism constructive. Anyways, Ezreal was my first main and I've seen alot of people do it wrong. For a while i just stuck with Booshido's AD Ezreal build and that helped me alot. I still think its a good guide but this is simply my opinion of how to play him.

I think armor pen is the best way to build Ezreal's runes. I get attack speed glyphs for a small boost and armor yellows to help out a little bit in the beginning.

I go with a 9/0/21, making sure to get the ghost and exhaust masteries if you go with those spells. I almost always get first blood with those two spells in mid. they overextend just a tad and they cant get away.

pretty standard AD skill sequence. If youve played him you know how good his q is compared to his w. At least as AD Ezreal.

Pros

He hits like a truck
extremely good poker
cross map ulti can ruin days
good early and late game if played right

Cons

Can be very squishy.
Often focused in team fights
People might make fun of your dance

Always try to get the solo mid. He can solo top if necessary but he shines in the mid.

Spend most of the laning phase harassing and last hitting minion, try to kill the enemy mid often. (First Blood is easy if you bait them out a little bit). I hate to say it but spam your q at enemies. It has low cooldown, low mana cost, and hits hard. It is my favorite skillshot in the game.

After you get level 6 you can tell your team to give you heads up on low hp enemies (especially ones hugging turrets) ulti across map and hope for the best.

Hopefully by this point youve got good CDR and decent damage output. Your ult should have about a 66 second cooldown so dont be afraid to use it. Ezreal can easily push lanes and take turrets and he can also gank exceptionally well with the ghose/exhaust combo. Also his e move makes him a pretty exceptional ganker. However avoid champs who can CC you. i.e. Pantheon, Sion, and Amumu. Target squishies and coordinate with teammates.

you should have about an 87% crit chance and decent attack speed that increases when you hit with your abilities. They should be afraid of you by this point. One thing about a lot of Ezreal builds is that they dont focus nearly as much on his basic attack as they should. Ezreal hits hard guys, don't be afraid to auto attack when you crit 700+

Please rate and comment as this is my first guide. I love you all and have a nice day!