Hello Guys, hers a guide to the champion, Ezreal. I really like Ezreal, due to his "built -in-flash" and his high damage out put in any fights. This build I am mainly focusing on AD, since that is what makes his Mystic shot ability strong.
My first time writing a guide, and I hope you like it.

For runes, you mainly want to get Armor penetration, so Greater Quintessence of Desolation and Greater Mark of Desolation. For the seals, is really personal preferences, if you like to spam your Q ability a lot early game (like me), I would go with the Mana regen per level seal. If you are not a spell spammer early game, the flat cool down seal would be great through out the game. The glyphs are flat cool downs, always nice to have the extra CDR for his abilities.

Pretty simple standard 21-0-9 masteries, maximizing the damage output.

For the last few items, it varies according to game play, lets say the opponent team is heavy on armor build and HP, Madreds and Last Whisper would be nice, the percent damage from Madreds and the Armor penetration is an exact fit. Some times I just want to have some fun with 2.5 attack speed (after stacking with my passive), I would make a Phantom dancer.

Always try to get middle with Ezreal, this can get him an early advantage in-terms of levels and gold. First blood is very easy with Ezreal, mainly because of his ultra long distance Q ability.

Fet a few shots on the opponent champion, get some regular attack, ignite and chase for about one or two more Mystic Shots, Tah-dah, first blood in 2 minutes.

Try to last hit minions as much as possible, while harassing the opponent champion, using your standard attacks and the Q ability.

Ezreal can get a lot of early game kills as well, harass the opponent champion to about half their hp, arcane shift in (land as close as possible to the champion, so the arcane shift damage isn't wasted on another target) Mystic shot, standard attack, if the champion starts to run away, keep sttacking them with your standard attack, and use Mystic shot when ever is ready, ignite them as the end, "an enemy has been slain". If the enemy champion decides to stay and fight, pop on an HP pot, keep standar attack and your mystic shot, arcane shift to another side of the champion, ignite. Another easy kill.

Lets say for any case, the enemy manages to escape from you, with low HP (your attack and ignite), take a look at where they are running to, aim your ultimate, SNIPED!

You are looking for teleporting back to base around level 7-8, getting the boots and sheen. I usually dont find it hard to farm for gold that is enough to get my sheen AND Berserker's greaves, just last hit minions.

This is when Ezreal should start going sround looking for ganks, with his extremely high damage out put, it is very useful in a team fight.
Pay some attention to the mini map, and you might find a chance to use your ultimate and snipe enemy champions from a long distance.

Ezreal should never initiate, she is the person who sits at the back of the fight, spamming standard attacks and mystic shots, maximizing damage to the enemy team.
Also, dont forget to simply click on an enemy champion and check out their armor status, do not target an enemy with high armor in a team fight, you wont be able to do as much damage as on other champions.

After a team fight is initiated, Ezreal can use his ultimate immediately, giving him the stacks from his passive also the damage to enemies. Then pretty much click on the "squishy champion", and auto attack.

If a team fight has failed, definitely arcane shift out, if still being chased, always run into a jungle, and flash through a wall/trees. Double flashing saved me SO many times, I cant even count them.

This is when Ezreal should be dominating, and having other players run away from you.

With almost 2 attack speed(or even higher, depending on your build), Ezreal can take down almost any champions in seconds. If there are tanks, get Madred's, with the slow effect from Trinity Force, it wont take that long to being a Tanky hero down, considering that you also have ignite to slow their HP regen.

At this point in game, Ezreal's ultimate is really used as a snipe for run aways, or stack for steam fight, most of his damage come from his standard attack and mystic shot.