Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Lets start off with my choices of Summoner skill. Well i chose cleanse for escaping those annoying stuns and Flash is great if your Arcane Shift is on CD and need to escape or catch up to an enemy.
I start off with a Sapphire crystal 1hp and 1mana pot. Starting off with a Sapphire crystal helps you spam your Mystic Shot for early last hits and harassing.
Then once i farm enough i run back to base to get sheen and boots. Sheen is very helpful on Ezreal since he spams Mystic shot alot and triggers the Sheen effect.
You can choose to skip merc boots and head on to The Black Cleavers. The Black Cleavers work effectively with Mystic Shot and decks out alot of damage.
By then the game SHOULD be over but if not hurry on for Trinity force. Its effects also go with Mystic shot.