Ezreal is a AD Carry that often goes bot lane with a support.

PROS
- Ezreal can kite or poke well
- Has a great escape
- Global Ulti that can hit anyone on the map
CONS
- Unless W when playing ADC
- Not the most Damage late game (but still very strong)
- Easy to kill when he doesn't have flash or his E

Q - Mystic Shot: Long range poke and applies on hit effects (very good). This means, it can crit and has spell blade (Trinity Force 200% damage, Iceborn Gaulet 125% damage). This ability is Ezreal's main source of damage.
W - Does almost no damage for ADC but you can use this move on ally to gives attack speed buff.
E - Arcane Shift: Instant jumps to a place you want. Can jump over most walls. Make sure you save it as an escape and only use when you are securing kill. Sometimes use it to harass only if you are near turrets or in a very safe spot.
R - True Shot Burrage: Launches a wave and damage that damages everything it's way but less damage when more targets are hit. Deals good damage mid game at level 6 - 9. Doesn't do that good of damage late game. Can be used to clear minion waves far away and dealing damage to other lanes to help out your allies.

Summary: Q a lot. Don't use W as damage but as a buff for allies. Don't burn your E unless needed to secure a kill or in safe position. R help other lanes or use it mid game to surprise your opponents or to secure a kill.

P.S. A neat trick: Aim Ezreal's Ulti at opponents base when they are low and are recalling. Time it perfectly and you can kill them in their base right after they recall!!!

Highly Recommmended:
Trinity Force gives Ezreal 2x damage on his Q.
Manamune gives around 70-75 damage and bonus magic damage on auto attacks and Tear of Goddess(manamune's sub item) gives Ezreal mana so he doesn't run out early game.
Blade of the Ruined King: Does 5% of the other person's heal. Really good on tanks. 5 auto attacks gives you BONUS 23% damage of your opponents health.

Recommended:
Infinity Edge: Soo much damage when you crit.
Guardian Angel: Ezreal's easy to kill. This gives him the ability to revive when killed.

Situational:
Iceborn Gaulet: Has slow but not as much damage.

Others:
Look up at the item section. Try out different things!! There's isn't one best build.

Runes:
Lifesteal is very good because Ezreal is easy to kill.
Amour pen is good against Tanks.
Extra Armor and Magic Resist is always a blessing.

Masteries:
Get Attack of course. He's a ADC.

Ezreal does damage. That's his role but that doesn't mean he will dominate everyone.
It's important for people to understand.
His support is the most important thing to him. Generally, Ezreal doesn't have crowd control so picks such as Taric, Sona, Leona, Nami, and Thresh are very good with Ezreal.
Another important thing about Ezreal is that you need to have very good positioning. Always respect your tanks because if you jump into a fight, you can get killed fast. Stay behind your tanks as you do tons of damage.

Thank you for reading my guide. I play Ezreal a lot and I think he's a God tier ADC but takes a lot of good teammates (support, tanks, and jungler sometimes) to dominate. Please comment for criticism or if you liked this guide. (my first one)