Hi, I am Mizaninnn - Diamond V in Vietnam - and here's my guide on how to play CDREz.

PROS:
+ Safe laner
+ Lots of poke
+ Very mobile
+ Attack speed steriod passive
+ Low cooldown
+ Look so cute
+ Good farming
Cons:
- Low range
- Completely reliant on skillshots
- Hard to come back if behind
- Requires good positioning
- Hard to hit ult

Rising Spell(Passive) Rising Spell Force
Auto attack steroid that ramps up after hitting spells in a row. Make sure to consistently use abilities on creeps and allied champions when pushing turrets to get the most effectiveness out of this.

(Q) Mystic Shot
Cooldown: 6/5.5/5/4.5/4
Your main damage dealer. It has a long range to help you CS better and play safe. Use this basically as much as possible since it it refreshes all other abilities by 1 second. It can check brushes, steal objectives, hit over walls, anything you want!

(W) Essence Flux
Cooldown: 9 seconds
This is basically just a small extra damage dealer or passive stacker. When your team stacks up you can throw this onto them to grant them and yourself more attack speed. I would recommend not using this at all when trying to harass. It's 100% better to save the mana for a Mystic Shot or Arcane Shift.

(E) Arcane Shift
Cooldown: 19/17/15/13/11 seconds
Main escape ability that also does damage to the first target in the direction of where you aimed it. Use this as an offensive tool very wisely. You cannot just jump into a fight with this and live. 90% of the time this will be used backwards.

(R) Trueshot Barrage
Cooldown: 80 seconds
High damage AoE ability that also stacks your passive. The best way to use this is to Arcane Shift into a brush and then immediately use Trueshot Barrage to surprise them. Make sure to watch out for low health enemies everywhere for a free kill!

Starting Items
Doran's Blade is basically the only starting item option available. It gives you great early game stats and sustain to help you trade and farm easier. The Warding Totem is a key to your early game as well. You should put this down at 1:30 either in the Tri brush if you're on blue side or over the wall into the river brush if you're purple side.
CDR build can give you -35% cooldown
Blue build is named that way for that all the items Ezreal build are some shade of blue. You should always rush Sheen for the damage and ability to lane. Buying a Tear of the Goddess first is very greedy and risky since it's not an offensive stat and the enemy bot lane can heavily punish you for it just by being stronger. Tear after Sheen will not slow down your stacking process by all that much since Ezreal can quickly stack it by spamming his abilities.

After that you should look to recall with enough gold to upgrade your Tear into a Manamune because it will greatly increase your stacking speed and help you hit your power spike as soon as possible. Then you would want to finish your Iceborn Gauntlet and you can start poking and slowing down your targets.

Last Whisper is a very important part of this build because you are doing 100% physical damage including the Muramana procs. Ionian Boots of Lucidity is the best choice for this build as you want the get as much CDR as you can so you can spam your Q and keep proccing your Muramana, Iceborn Gauntlet, and Blade of the Ruined King.

Like a C9Sneaky's playstyle...
Basically all Ezreal is about is outplaying people with his Mystic Shot. You have to outsmart the enemy in lane and find angles that your Mystic Shot can hit them in. Remember: your Mystic Shot certainly on target

(Early Game)
Early game all you want to do is last hit with your auto attack when you wont get hit back for it and then shoot a Mystic Shot when you would get punished for last hitting. You don't win all-ins until you hit at least a few Mystic Shots on them first.

Upon hitting level 6, if you're support can stun-lock the enemy long enough for your Trueshot Barrage to get off and hit them then you can instantly win the lane. Your ultimate does insane damage to lone targets.

For the matchups you do this to every single enemy so I'm just going to put difficulty ratings on how hard they can potentially zone or dumpster you.

(Mid Game)
Try to look for opportunities to get free kills with your team. 1v1ing people is pretty hard unless you can manage to pick up a red buff to do so. You should have your Blade of the Ruined King as well at this point so a red buff + Blade of the Ruined King is going to devastate.

You probably don't outscale most ADs so look to end it before it gets too late into the game. You'll always be safer than other ADs but the later it gets the more deadly they are.

(Late Game)
At this point you're either super fed or decently fed and the enemy ad is outscaling you depending on what it is. Try to get a 5-man ultimate and close out the game with your team. You're really just looking to catch someone off-guard with your burst. Look to bait baron with Vision Wards and your team or push down whichever lane you have outer turrets left in. Dragons at this point give a huge amount of gold too, so make sure to prioritize them as well.

(Team Fights)
Go for the 5 man Trueshot Barrage to instantly get full stacks on Rising Spell Force. Snipe people with Mystic Shot and Arcane Shift backwards. Deal as much damage as possible. Try to hit the squishier targets with Mystic Shot whenever you can but other than that kill the tanks.