this guide is still work-in-progress.
stay tuned for effects on buffs or nerfs

this is an not-yet-in-depth guide for graves, so sit tight and enjoy the ride. :)

why you should use graves

pros:
-crazy close combat burst
-high aoe damage output
-jump over walls with quickdraw
-durable when he's in combat with his passive, gunslinger.

cons:
-starts off slow
-squishy if out of combat

example runepage 1

a general ad carry runbook might looks like this:
Greater Mark of Desolation (15 flat armor pen)
(13 flat armor)
(13 flat magic resist)
Greater Quintessence of Desolation (7 flat armor pen)
(26 flat health)

this runepage aims to give graves a balance stat with both offence and defence

example runepage 2

if a balance stat isn't your cup of tea, this runepage might suit you:
(15 flat attack speed)
(7 flat attack speed)
(6 flat attack speed)
(10 flat attack speed)

attack speed is also great for graves, especially combined with quickdraw. this runepage aims to give graves a hell lot of attack speed. and if you're using this runepage, make sure to take exhaust instead of ignite.

always take
flash - flash is used in both offensive and defensive:
offensive: chase enemies, land skillshots like buckshot.
defensive: blink out to escape sticky situation, hop over a wall, dodge skillshots.
bonus: you have a double wall jump from flash and quickdraw.

recommended
ignite - ignite deals true damage and reduces healing and regeneration effect. its best used to get first blood or counter champions with self heal like vladimir and warwick.
exhaust - exhaust slows movement speed and reduces basic attack damage. just remember not to use on a master yi (while using highlander) or olaf (while using ragnarok)

1.
as any ad carry, getting doran's blade is the typical way to start. having 10 attack damage, 100 health, 3 life steal is not a bad first item.
alternately, starting with a boots of speed or a vampiric scepter is also a good first item, boots of speed will soon build in berserker's greaves and vampiric scepter will soon build in the bloodthirster.

2.
once you have at least 1500gold, find a time to recall and pick up another doran's blade and berserker's greaves. stacking doran's blade is under-rated but having just two is enough to save for the bloodthirster.

3.
it should be at mid-game and you should have some kills. getting the bloodthirster is essential to graves and rushing the bloodthirster gives you an advantage to stack the passive. also you should being able to get phantom dancer and a last whisper. phantom dancer gives you attack speed, critical chance and movement speed, which is great for graves considering his low movement speed and if you're not using a attack speed runebook, and a last whisper gives you some attack damage and most important armor pen, since armor becomes a big deal.

4.
let's make this short. it's time to get your last items, frozen mallet and guardian angel. frozen mallet makes you a little tankier with the 700 health and guardian angel is a really good last item on graves since you're a major threat and everyone will try to kill you first at teamfights.

5.
item substitutions:
mercury's treads. get this if enemy is a heavy cc team.
youmuu's ghostblade. all this really shines is the cooldown reduction and armor pen, you can substitude this with last whisper.
the black cleaver. get this if you're playing attack speed, the passive works better.
infinity edge. again get this if you dont like last whisper.

skill
buckshot ( graves fires three bullet in a cone, damaging all enemies in their path.) - this is a great damage output with a low cooldown, a good harassment on your lane.

smoke screen ( graves fires a smoke canister at the target area creating a cloud of smoke. enemies inside the smoke cloud have reduced sight range and movement speed.) - this is most a support skill, just like a small nocturne's paranoia.

quickdraw ( graves dashes forward gaining an attack speed boost for several seconds. hitting enemies with basic attacks lowers the cooldown of this skill.) - this is a great skill, first of all you can junp over a wall with it, and the attack speed given to you is amazing.

skill sequence
1v1: start with smoke screen, and then buckshot and quickdraw and let your basic attack do its work, if your enemy tries to escape, quickly land a collateral damage to finish him/her off

please try my guide out and comment :)