Hi, I'm Laterally. Although I am not 2000+ elo, I think I know how to play Ezreal. For me, I play Ezreal as a straight damage carry, not getting any survivability items. Some people might detest, but you should be far back enough to avoid getting jumped on. Anyways, yea. Ezreal has a very high skill cap, mostly dependent on his skill shots and how frequently you land them. Practice, practice, practice. He has a very good blink, a q that reduces cooldowns, a w that slows enemy attack speed and increases ally attack speed, and a global ult (but its not very strong).

Classic AD Carry runes. You can substitute the attack damage runes with armor pen, but it's all about preferences.

For masteries, I went the standard attack damage masteries, but I added utility because the added mana is always nice (kinda. It just fills a spot really), the movement speed is really nice, and the Runic Affinity is super nice when you have a buff. I love getting red, so it's essential for me.

The early game item sequence can be switched around sometimes. I like to switch the zeal for phage sometimes for more poke damage and the health. Also, you can get the vampiric scepter whenever you want really. You can get it really early if you're getting poked in lane super hard. If not, you can until after trinity force. The trinity force is IMPERATIVE for damage output, especially in lane. The sheen adds so much damage with your q. The blood thirster I usually get after infinity edge because the vampiric scepter is usually enough life steal. For your last item though, you can get whatever you want. I like to get another blood thirster for the extra damage and life steal. Makes you sometimes impossible to kill because you life steal too hard with your crits.

Q for poke
W next for flash
E last because its weak, but get one point early because of the attack speed shift.
R whenever you can. It's pretty good. Sometimes it lacks damage though :/

Never leave without flash
Ignite is good for securing kills in the laning phase. It's also good for those with high regen or lifesteal.
You can also go heal, but its not very useful late game. Only in lane.
Cleanse is also pretty good. Gets you out of all cc's and annoying poop like ignite :P

Those are the only ones you should get really. Nothing else is useful.

Have fun! Ezreal is a fun champ!