This guide isn't going to go too deep. I've focused on just highlighting the essentials of this build by briefly explaining his abilities, rationalizing the items, and highlighting the play style of this build. I have edited this build since it's original version, as the first few comments would have you believe, it needed some revisions. I've tried to adjust the guide to be more user friendly, however, I stand by this build. Thanks for reading!

Game Start:

I always lead off with Boots and 3 Health Potion. Even since the Nami update, and all the changes to boots, I find it to be a good way to go. However Doran's Blade can work too. It's all in preference, though with the right runes and masteries I find Ezreal to have enough kick to get by without any damage items, while saving for the B. F. Sword. After acquiring your B. F. Sword, finish your boots with Berserker's Greaves for the additional attack speed.

:BloodThirster

This is a must have in my opinion. Early game until some attack speed can be built up, you will rely on the burst damage from your abilities, and this will give it to you. If the game is going well enough that you can rush B. F. Sword, then finish Bloodthirster immediately following Berserker's Greaves.

:Guinsoo's Rageblade

I like this item because it stacks AP and AD. Thus giving some extra damage to Essence Flux and Arcane Shift as well as stacking both AP and AD damage to Mystic Shot and Trueshot Barrage. Although you won't be relying on AP for your main damage output, it will add a bit more damage against enemies with high armour.

The other benefit to Guinsoo's Rageblade, and the main reason I pick it after Bloodthirster is it's passive. Continually stacking attack speed and ability power as you attack with abilities and basic attacks. Combined with Rising Spell Force this gives Ezreal a big attack speed buff beyond what he would other wise have, allowing you to make more room for other high damage items.

Mid game:

:Runaan's Hurricane

I often take this next after rageblade. It alone gives a high base attack speed, as well as providing a passive that shoots out 2 additional bolts with every basic attack, which are less useful for fights, but extremely useful for farming. It's nice to get it out of the way if the game is going favourably enough, as you can then forget about acquiring attack speed and use it to farm for more end game damage.

:Hextech Gunblade

This item requires less thought, it's good if you take it, and it's fine if you take something else. The goal at this point when picking your fifth item is to Get More Damage. I often go for the Hextech Gunblade for the additional life steal/spell vamp, as well as the AP and AD damage to assist with basic attacks, and add damage to all of Ezreal spells. However if it doesn't do it for you, take something else.

:Blade of the Ruined King

When building a Hextech Gunblade I always start with the Bilgewater Cutlass. You're an ADC, and whether or not you incorporate a little magic, AD should be the focus. However if you decide not to finish the Hextech Gunblade or that you don't want the magic. Blade of the Ruined King is a great way to go.

Final Items:

There is a good chance the game will be over before you get to a 6th item. Often before even completing your 5th item. If you do though, you're either really fed, or it's a close, long game, and you'll want to weigh the situation when picking this item. If they're defending well, or have a tank that you're having trouble killing, you may want armour pen, or if you just need one last push to win, and want as much oomph as possible, maybe just a bit more damage is all you need.

: Last Whisper

This can be a great finishing item. It gives a but more damage, then allows you to jab a big hole in the opponents armour. If you're finding some opponents hard to hurt, this might be you best friend in bringing them down.

:Infinity Edge

This item , although I would never rush it, can be a good pick for either your 5th or 6th item. At either time if you find yourself needing damage. Take this guy, It provides a lot of damage, and you'll be doing a buffed critical hit on every 4th or 5th basic attack. The only issue with it is it's price, but if you've been getting ample farm with Runaan's Hurricane you may not have too much of an issue getting it.

: Black Cleaver

This item can be take at any time without remorse. It's an all round fantastic item. If you find yourself struggling early game and can't wait for a B. F. Sword to get some damage, then build Long Sword --> The Brutalizer --> Black Cleaver. Get Bloodthirster later. Black Cleaver is a good pick at any time. It gives some extra health, some armour pen, and more damage. So if ever you think you need it, build it.

Summoner Spells:

I personally see Flash and Ignite to be the most logical spells, and I don't know that I would be convinced to try something new.

: Flash
Yes Ezreal has his own flash, but this is just doubling up on the good! If you're that desperate to escape it can be a life saver, but it can also just sharpen the edge given you by Arcane Shift to quickly re-position in fights in order to secure continuous damage output, and in many cases, kills.

: Ignite
Some call it cheap, but it's given us by the game, so make use of it! Early game this can be all you need to get your first kill. It finishes off enemies that may otherwise have been able to get away. Or, if you die it can ensure that your killer follows you to the grave.

Alternates:

Ghost: Ghost
This could be useful for chasing, and running away, and in certain situations may be better than Flash For pursuits, however it won't allow you the same angle optimization that Flash does in fights. Which in my opinion is more valuable.

Abilities:

:Mystic Shot

This is your friend. Take it first, max it first, and spam it. It decreases the cool down on all your abilities, and is your most consistent form of damage. You're pinky should never leave Q.

:Essence Flux

I wish they could revise this ability somewhat. I often use it pre-6 for a bit of extra harass. It is useful in that it goes through minions, and pre-6 it does some damage, however after that, when building AD, it is useless so far as damage. It does increase the attack speed of allies though. So if you have an ally who thrives off attack speed, such as a jungler like Udyr or Warwick, and you think of it, then send Essence Flux their way in a fight. Other than that though, you can basically forget about it unless you built both Guinsoo's Rageblade and Hextech Gunblade. Even then, Essence Flux will be little of little priority to you.

:Arcane Shift

Like Essence Flux it's not going to be used often for damage. Use it to escape, chase, or re-position for a crucial Mystic Shot. Take second, and max second. Not for damage, but to decrease the CD. The more often you can get Arcane Shift up, the safer, and the more deadly you will be.

: Trueshot Barrage

This is what makes Ezreal so fun right here. A global ult like Ashe Crystal arrow, except it can actually kill people. This can go through multiple enemies, make it good for team fights, and can be used to snipe from across the map. It has many applications that I won't begin to lay them out for you. Like any ult you should decide the right time to use it, but unlike other ults, it's CD can be shortened. Spam Mystic Shot to ensure Trueshot Barrage comes back really fast in time for the next situation you may need it.

Unlike some burst champions like Katarina that require a certain sequence to maximize damage, or champs like Jarvan IV that have specific sequence to land a knock-up, Ezreal is less defined by a certain formula or sequence. How you use your abilities will vary with the situation, but I'll try and lay out some examples.

Early Game

At this stage I'm more concerned with last hitting minions, than harassing the enemy, but I never pass up an opportunity if it arises, and it's so satisfying seeing your picture to the left of the ""FIRST BLOOD"" caption on the screen. Like I've already discussed. Use Mystic Shot a lot. Harass with it, and lead with it on engages. After acquiring Arcane Shift at level 2, the enemy will be weak enough that Arcane Shift will do some damage. So, if an enemy is caught out of position or your support/tank is able to make them vulnerable to you, then engage fast. Arcane Shift can close any gap there may be, and if close enough, damage them. Use Mystic Shot then pop ignite. Try to ensure you land every basic attack you possible, while being ready to use Mystic Shot again when it resets. It may be behind their turret, but they should die if you've hit them enough. If it's up Essence Flux is good for hitting them through minions, and although it's nothing compared to Mystic Shot, anything counts.

After acquiring Trueshot Barrage I start playing a bit more aggressively. If an enemy gets away at low health, and ignite is on CD or you don't get a chance to land it, then Trueshot Barrage should finish it up. Before this, Focus on creeps and get that gold!.

Mid Game

After getting your Bloodthirster and Guinsoo's Rageblade, you will still be relying on burst damage from your abilities, primarily Mystic Shot. You will have some attack speed now though, just not enough to stand and fight, so you'll have to play the kiting game a bit.

Harass with Mystic Shot
Basic attacks,
Mystic Shot
Basic attacks.
Arcane Shift To gain some distance and continue.

You will have a decent damage output but it's still best not to engage alone. You'll be most useful in team engages when you can land your abilities and basic's from behind your initiators.

Late Game:

After getting a close to full build you should have a lot more kick. At this point both your Abilities and basic attacks will be doing good damage. In any engage be sure to lead with Mystic Shot before proceeding with basic attacks, and continually use it to keep up attack speed stacks and reliable damage. As I said before it's less of a sequence, and more repetition. Mystic Shot, Basic attacks, and maintaining distance from target with Arcane Shift.

1v1:: Melee:

Engaging a melee target still requires some kiting. Chances are they are beefier and have a more bursty damage output. So kite and harass until they are low and you are certain you can chew them down from there.

1v1: Ranged:

Against another ranged I like to close the gap. Instead of dancing around eachother's Skill shot's, I use Arcane Shift to "Poof" into their bubble, applying the pressure. You should be certain though, that you can outmatch their damage, and that the life steal available to you is enough to sustain. I also use smart casting, or at least the smart cast indicator so that after closing the gap I can still land my skill shots without trying to maneuver the long arrow at such a close range. Being close itself doesn't necessarily do more damage, but it can appear as a huge flex of the muscles which can intimidate the target causing them to panic or flee. This also keeps them in your range longer if they do try to flee, making a kill more certain.


Team Fights:

As an ADC you often just want to hit what's in front of you. Not that you necessarily "Should" but depending on your team, and the quality of an initiation that may be all you can do. However if your team manages to focus really well on the main threat, Stay behind your team and hit the threat with everything you have. Once that threat is down, focus on picking off those with the lowest health.

As a general rule, Never engage in a team fight. Hang in the back, and once the fists start flying, aim for the heart. Of course the enemy threat should always be focused, but they can't always be reached. Remember too, on your team, YOU are the threat. So you don't want to expose yourself. You dying is an extreme advantage to the enemy. After your team engages, pick your target and assist your ally in bring them down. You're the main damage doer, so focus a target, bring them down, because as soon as they are down, both you AND the ally fighting them can move on to another target, and the success snowballs from there.

Stay to the outside of the fight in order to stay safe, and pick good angles. If the fight's either winding down, or not going as well as planned, Trushot Barrage can be invaluable in damaging many enemies at once or cleaning up low enemies that may try to run, and can either turn the tides of a sour team fight, or make a successful team fight, an even greater victory. Sticking to the outside will ensure more targets can be hit.