Hi, I'm a ADC main and have been an ADC main since Season 5.

Yes, I have subjected myself and endured the "incredibly fun" meta's that ADC's have to deal with such as:
- Lethality meta
- Tank meta
- Ardent Censer meta
- AP Bot lane meta
...

The list could honestly go on forever.

I have just accepted the fact that ADC's currently (Season 12) have no impact and never really had an impact on whether you win or lose your game since Season 7 and still play the role since its my comfort pick and hope to create guides to convince others to pick up the role or play a certain champ.

Note: Unlike my 'Challenger Karthus guide which prints LP' which was obviously a joke, this is a serious and legitimate guide on playing Ezreal

When To Pick Ezreal
Ezreal is generally a safe-pick against most ADC's aswell as a blind pick. This is because of his ability to escape ganks or potential engages with Arcane Shift as well as his ability to CS and poke from a safe distance with Mystic Shot.

When Not To Pick Ezreal
One of Ezreal's biggest downside is poor wave clear. This means if you are against an ADC with good wave clear like Sivir the lane can be quite difficult as you are always going to be playing under your own turret.

Ezreal also struggles to deal with early aggressive laners such as Draven or Lucian (or Leona/ Nautilus support wise) due to his lack of damage before getting a few items and his lack of wave clear.

As such, I would generally avoid picking Ezreal if you can already see the enemy team has an aggressive bot lane.

Flash Flash should be quite an obvious choice and will always be one of the spells you take.

Teleport Teleport is an important spell on Ezreal because (if you decide to start Doran's Blade, Doran's Shield, or Long Sword) it gives you control over minion waves. It also allows you to purchase Tear of the Goddess at a favourable time, when the wave isn't crashing under your turret. To do this effectively you should: 1. Farm until you have enough gold to buy Tear of the Goddess on your first back. 2. Once you have enough gold, begin shoving the lane (your support should help shove the lane). 3. Then recall, buy Tear of the Goddess, and immediately Teleport back to lane. By doing this, you are able to begin stacking Tear as soon as possible without losing any CS.

Heal Heal is also another standard and safe spell to take. However, I prefer Exhaust or Teleport on Ezreal. Despite that, I would take heal if my support is taking Exhaust

Exhaust Recently Exhaust has become the standard spell for ADC's to take. The reason for this is because of the surge of AD champs such as Bruisers and Assassins. As such, if the enemy has a lot of AD or you want to play aggressively and all-in your lane early on I highly suggest taking Exhaust.

Cleanse Cleanse is a situational spell which can save you from using up an item slot for Quicksilver Sash, but I personally believe that its better to go a different spell like Heal or Teleport unless their team has incredibly heavy CC.

Keystone Options

Conqueror Personally, I like to take Conqueror on Ezreal at the moment as it suits my playstyle (being very aggressive and trying to all-in early on). Conqueror is a good rune on Ezreal if your support is aggressive and can all in early on such as Blitzcrank/ Thresh/ Leona. If your support chooses a poke or shielding/healing champ such as Brand/ Soraka then I would recommend taking First Strike instead.

First Strike First Strike is another option for Ezreal to take as it gives him more poke damage and gradually grants gold. However, if you have an aggressive playstyle or an aggressive support such as Blitzcrank or Thresh that can net you early kills (especially against weak early game supports or ADC's like Yuumi or Zeri) it is much better to take Conqueror.

Secondary Tree Options

Presence of Mind Presence of Mind is a good choice on Ezreal as he uses a lot of mana early on when CSing and poking with Mystic Shot. As a result, Presence of Mind allows you to continually poke the enemy laner without burning through your Total Biscuit of Everlasting Will's.

Triumph Triumph is another option to take on Ezreal since he has low base health (being 530), however I believe that Presence of Mind is still a better choice overall as it benefits Ezreal more.

Biscuit Delivery Biscuit Delivery is crucial on Ezreal as he heavily relies on mana early on. Although it also restores health, you can barely tell the difference in your health so try to avoid using it to gain health unless its desperate (E.g. You barely escape a trade/gank and you're Ignited)

Magical Footwear Overall, Magical Footwear is better on Ezreal when choosing secondary tree paths for Inspiration as if paired with Teleport can easily let you back and TP back to lane without losing any CS and back at favourable times. However, if you really don't like waiting 12 minutes max for Slightly Magical Boots you can switch it out for Perfect Timing

Perfect Timing As I mentioned above, Magical Footwear is the better overall option, however if you are fixated on building something like Guardian Angel or even potentially Zhonya's Hourglass during the game and could use an early Stopwatch for lane, then it's fine to take this rune.

Starting Items

Doran's Blade In general, Doran's Blade is the most common and standard starting item. Due to Ezreal's base health being so low compared to some other meta ADC's at the moment, Doran's+Pot is the most consistent starting item.

Tear of the Goddess Tear is a good start if you aren't vsing an aggressive lane like Draven + Leona as it allows you to start stacking Tear from the beginning of the game, and you can potentially take Exhaust or Heal instead of Teleport. However, even if you aren't vsing an aggressive lane, it can still be risky due to his base health.

Long Sword Long Sword is another risky start due to Ezreal's base health and shouldn't really be taken unless you're against another ADC with low base health like Zeri. However, even if you're vsing another low base health ADC and decide not to take Doran's Blade, Tear of the Goddess is a better start than Long Sword in my opinion.

Doran's Shield Doran's Shield is a much less common starting item, however may be necessary if you are against a losing matchp like Draven or Sivir, or even a strong poke lane like Jhin + Xerath. It allows you to sustain in lane and still reliably farm in lane, but you will most definitly be more focussed on farming and poking rather than trying to go for trades or kills.

Core Items

Essence Reaver Essence Reaver should generally be your first item (even before your mythic) as Ezreal really lacks damage early game compared to some of the other meta ADC's at the moment. Additionally, Ezreal also has a mana problem due to spamming Mystic Shot, and thus can reliably restore mana using Essence Reaver.

Manamune/Muramana Muramana should come as no surprise when playing Ezreal. This is because it allows you to spam Mystic Shot. On top of that, once Manamune transforms into Muramana you gain an insane damage stats and can very quickly start scaling.

Crown of the Shattered Queen Now this may seem like an odd item since Ezrea is not an AP champ (although admitedlly AP Ezreal is fun in URF) however, despite Ezreal having somewhat decent AP scaling on his abilities, you definitely don't build this item for its AP stats. Instead the item's other stats (Ability Haste, Health and Mana) are quite useful for Ezreal as it allows him to continually spam Mystic Shot, gives him more health (making up for his lack of health early on). The main reason you build this item though is due to it's unique passive. Gone, are the days of staring at a grey-screen due to Zed's Death Mark. Gone, are the days of Rengar doing a drive-by kill on his way to Drag. Gone, are the days of Kha'Zix one-shotting you in 0.01 seconds. The 75% damage reduction you receive from this item is the penultimate reason you buy this item. In particular, it is effective against assassin's as generally assassin's don't have a way to reliably proc Crown of the Shattered Queen without committing to an all-in. Additionally, you can reliably 1v1 the enemy ADC even if they're fed due to the insane damage reduction.

Situational Items

Executioner's Calling Nothing much to say here. This is simply just Anti-Heal item you build if the enemy team has a lot of heals.

Quicksilver Sash Again. No surprises. Build this if the enemy team has a lot of CC.

Guardian Angel No surprises. If you're somehow getting one-shot or dying too quick during or before teamfights.

Counters

Jinx Jinx is a hard lane due to her ability to push you early due to her excellent wave clear using her rockets. Moreso, even if you do manage to survive the laning phase (by playing passive and farming) Jinx is a late game monster compared to Ezreal and can easily carry a game if she's fed and doesn't get caught out.

Sivir Sivir is a pretty hard matchup for Ezreal because from the start of the game she will constantly shove you under turret using Boomerang Blade + Ricochet, especially since you have no wave clear to try and shove back. Another reason she can be problematic is because of Spell Shield which can absorb any incoming Mystic Shot if she doesn't have any minions to stand behind.

Syndra Syndra is pretty annoying to lane against due to her early wave clear and poke using Dark Sphere + Force of Will and can land some early stuns with Scatter the Weak if you're not careful. However, Syndra's main scariness comes from synergies with her support. This includes supports like Senna or Zilean who can use Last Embrace or Time Bomb on minions and can get you killed in combination with Syndra's Force of Will. Although from my experience playing against her, the lane is still fine if you poke and farm from a distance, even with those kinds of support.

Ziggs Ziggs is problematic due to how much wave clear he has, how much poke he has, and how fast he takes turrets if you're not careful. Ziggs's Bouncing Bomb + Hexplosive Minefield lets him easily shove lane and can quickly whittle you down if you don't dodge it. Furthermore Satchel Charge can be used to engage or disengage from ganks but more importantly, if he shoves you out of lane enough times he can easily get first turret if you're not careful.

Yasuo Fortunately, Yasuo is a pretty uncommon/rare pick for ADC meaning you won't have to deal with this matchup very often. Although admitedlly, almost every Yasuo ADC is a Bronze Yas main with 1,000,000 MP whose trash and got autofilled ADC, BUT, if you do happen to vs a Yasuo who knows what they're doing and is good you will find this lane incredibly difficult. The reason Yasuo is a difficult matchup stems mainly from his Wind Wall which allows him to completely negate all your abilities and auto's, which can also be used to deny you minions and miss Canon creeps. Other problems include Sweeping Blade which lets Yasuo easily dodge Mystic Shot, and if you do manage to land one it will most likely just be soaked up by Way of the Wanderer which essentially negates the first bit of damage Yasuo receives. Finally, Yasuo ADC's usually ***** in champ select for their support to have knock up since they can't land their tornado's themselves so often you'll be vsing a Yasuo with an (almost guranteed) knockup support like Alistar, Braum or Gragas which makes it easier for Yasuo to cast Last Breath.

Laning Phase

Depending on the matchup will obviously change up your playstyle. However for the most part you want to poke and farm with Mystic Shot whilst trying to stack Tear of the Goddess as fast as possible.

If your support has heavy poke like Brand, Karma or Xerath then your goal should be to poke the enemy laner to a point where they're low and try to get a quick kill to get ahead early.

If your support has heavy early-game pressure like Blitzcrank, Thresh or Leona you can go for Level 1-2 kills with an early hook or CC chain on the enemy ADC or Support.

Teamfighting

As is the case with any ADC, when teamfighting as Ezreal you want to be attacking the closest enemy champion to you unless an enemy that's a higher threat is within your attack range.

Specifically with Ezreal you can stay pretty far back in teamfights whilst dishing out a ton of damage. Additionally, you can cast Arcane Shift to avoid any assassin's/bruisers/mages that may try to quickly kill you during teamfights. However, you can also use Arcane Shift aggressively to secure a kill so long as it doesn't put you in any immediate danger.