That's a decent build. I rush BT on every single adc but some people prefer to rush IE. Reasons why I prefer BT: Finishes sooner (especially since some build Vamp even if rushing IE), gives you (more, if you build a Vamp Scepter before IE) lifesteal, which is incredibly useful tool in laning. Rushing BT gives you more time to farm it up whereas if you get it mid or lategame you'll either charge it up slower or split up from your team (most of the time). In addition, crits and some champions abilities deal pretty pathetic damage without a lot of AD already (and nothing gives as much AD as a BT except a fully stacked Sword of the Occult. I would especially rush BT on Graves because a decent chunk of his damage comes from his Q and R, which scale on AD but not any other ADC stat. I generally get IE after BT because IE is what makes you able to out-dps bruisers for the most part (although, without the bonus AD of a BT it doesn't help nearly as much) and after that I get a PD or Shiv (depends on the champ) for more attack speed and crit chance. To round out my build I get some combination of another BT to increase dps significantly and double sustain, IE/Shiv (whichever I didn't get before, generally to augment my dps further as a last item) a Runaan's (almost always get because its actually a huge increase in damage in teamfights, on champs that have good synergy with it such as Twitch I get it sooner) or a Guardian's Angel if there are still enemies who can kill me (almost always) and I feel like I will actually be able to do something after respawning (not always). I don't think I've ever built a BotRK or Last Whisper on a champion as I feel like they are almost always outclassed by BT. After your build is done, consider selling Greaves for Zephyr. With a Zephyr and PD/Shiv, you'll still be as fast or faster than most other champions and Zephyr gives AD, Tenacity, and more Attack Speed. Make sure you're buying the Elixir(s) towards the end of the game. Also, I generally start with Long Sword 2 Health Potions because boots start is imo useless unless you really need hardly noticeable movespeed to dodge their skillshots, and Doran's Blade doesn't put me 400 gold ahead in my build if I start snowballing. Dagger is bad to start with because attack speed is not that good in pokes or early trades compared to flat AD.
On Graves I'd go Greaves+BT (I prioritize building BT and build the Greaves whenever I don't have enough for a B.F. Sword when I back) then if I'm snowballing an IE (Q and R scale on AD) and if not then a Shiv to keep up dps with 2 items and get a second sooner. After that you'd either get the other or Runaan's (Runaan's decreases the cooldown on Grave's E by 3 if both Runaan's bolts hit I believe) depending on whether you want more single target or multi target damage. After that I'd get the last one of those 3 and then either another BT (I don't think anyone can kill me, OR I just don't feel like I'm doing enough damage but its not because they're too tanky OR I want more health sustain), GA (I often get focused but feel like I can still do good damage without another damage item), or Last Whisper/BotRK (I'm not doing any damage purely because they all have so much Armor/Health).
Yeah that was a wall of text here's a tl;dr: On Graves go Greaves->BT->IE if snowballing, Shiv if not->whichever of IE/Shiv you don't have if want single target damage, Runaan's if want multi-target->whichever you didn't already get->BT if I don't die, GA if I do.