Try to play passive at the beginning until you reached level 6.
Graves ultis the key for his brust.
When you reached level 6 try to harras the opponent ADC with an auto hit followed by .
You can easily win trades in lane by using as a gapcloser or disengage.
is very important to confuse your opponents.
You can use smoke screen to turn around fights.
Use to burst down targets while they are blind, by using the combo :
auto hit, , auto hit, , auto hit. Make sure not to waste! It's the only usefull tool to chase down or escape out of sticky situations.

Mid Game is Graves's "time to shine".
After having finished your core items, your able to burst down the enemy carrys.
If u useand you will get enough attack speed to even deal a massive amount of damage though your skills may be on cooldown.
When you meet the enemy AP or ADC in a 1v1, make sure to use the combo from above, to burst down the opponent.
Never the less, Graves is no splitpush carry.
You want to make sure not to leave the backline in a teamfight.
Try to destroy the enemy Frontline but without using .
If possible save your ult for the carrys so you can burst them down before they are able to kill you.
Before a teamfight starts try to auto hit the enemy carrys as often as possible, but never use for it!

Late Game will become hard.
Graves's late game is not generally bad but it's even harder to burst down targets because the enemy frontline will stack armor and health.
You can still burst enemy carrys in 1v1 situations.
Because of this burst Graves is good when it comes to objective controle.
If the enemy jungler or any enemy carry trys to get closer to the objective, make sure to cut them off with.

Graves's damage to turrets is on average.

Graves's burst dmg is the key to win teamfights.
Important to remember is that you should never underestimate Graves's.
You can even finish enemys from larger distance by using .
When playing Graves you have to watch your positioning in teamfights like every other ADC.
Try to look for 1v1 situations so u become fed for the late game.

That was my guide about Graves's. I hope you enjoyed. =)