This is my guide on Ezreal. Ezreal is a ranged dps hero focusing on harrasing your opponents and dealing damage even behind tanks like Singed however Ezreal cannot initiate a fight unlike Ashe with her Enchanted Crystal Arrow.Certain carries like for example Gangplank who has to charge in front of the tanker to attack or wait till the tanker initiates the fight and charge in with his Parrrley which deals tons of damage but has a too short range. Ezreal how ever can use his Mystic Shot to hide behind tankers and deal tons of damage.His Mystic Shot has a range of 1100 compared to Gangplank Parrrley which has a range of 625.I will do a rough description through the runes and masteries as i will mainly focus on items/summoner spells/skills and farming.
'Any champion can be played,it is how well you can play it'

Items are the most important thing on every build
Doran's Blade is just neccesary for every ad carry as it gives health,damage and lifesteal.

Berserker's Greaves is for bursting turrets down and you can't just rely on your top laner to snowball the match as the top laner might sometimes be the tanker of the team you cannot expect Sona or Soraka to tank.

Blood Thrister is the 1st core item of the build its unique passive:Gain +1 attack damage and +0.2% life steal per kill (maximum +40 attack damage and +8% life steal). Half of the bonuses are lost upon death.This means that if you are snowballing already, it will be easier to get your health back and get more damage however if you do not snow ball, you can still ger 60 ad and 12% lifesteal.

Trinity Force is just a must have on ezreal.

the other two items are self explanatory

i take and however i do not take Flash or other spells like Exhaust as with my build there is no point of flash as you already have arcane flash and Exhaust with the same reason.i take Ghost for running to your lane and ignite for securing first blood and getting kills.

This is a video on the ezreal champion spotlight between riot's and colbycheeze's

RIOT'S Play Video ColbycheeZe Play Video i personally prefer colby's it is more detailed then riots.

this is colby's last hit video which is the best so far i've seen Play Video http://kills.so/

Laning:so when laning farm farm farm only harrass when your opponent has no minions and you will have a lower chance of using your Mystic Shot accidentally on a minion.
Escaping Ganks: Arcane Shift can allow you to escape ganks almost all the time unless your unlucky.To be extra safe when escaping ganks use your Arcane Shift away and Ghost away.
The most important thing when playing Ezreal in the laning phase is map awareness Ezreal is obviously squishy so when a player reports MIA or MS hide in a brush and farm if they specify the direction towards your lane run to hug your turret. Ezreal F.Y.I.:ezreal can do at every lane be it a solo or dual lane.In a dual lane,try to killsteal your teammate =P.Any random person who plays LoL will know to feed Ezreal.

Mystic Shot--> Ezreal fires a skillshot nuke and deals damage to the first damage it hits max this right away.
Essence Flux--> Ezreal fires a skillshot that will damage all the opponents in its path it can pass through minions.take a point early and max it last it is most useless when playing AD Ezreal but best when using AP Ezreal.
Arcane Shift--> Ezreal flashes away and shoots a homing missle to the nearest champion or minion.Take a point in lvl 2 and max it by lvl 13
Trueshot Barrage--> Ezreal shoots a strong barrage that has a global range and will decrease the damage 8% for every creature/champion it passes through.Take points in 6/11/16
Mystic Shot can be used to last hit minions or killsteal people. Essence Fluxis useless for this build. Arcane Shift use arcane shift to escape ganks or chase up to opponent. Trueshot Barragejuz use it like an Enchanted Crystal Arrow

For runes i think the best way for me is to get physical damage Marks and Glyphs and attack speed Seals and Quints.This setup makes me have high damage early game and fair damage late game but during late games all your items will be up and you do not need to worry about your damage.

For masteries i go with a standard DPS carry build that aims for giving me good damage.you may want to change it to give you CDR.