so this would be my regular run down build
but I honestly do not think its the build I've gotten plenty of kills but I have a hard time carrying teams even with a strong lead im just not good at adc im trying to learn save +_+[zombie-nunu-bummed]
DarkRitual1 votesDrop the cleaver and mallet. Grab Blade of the Ruined King and possibly Bloodthirster or situational item.
khorney1 votesyah that build sucks. blade of the ruined king, runaans, boots, ie, rapid fire and lastly essence reaver.. feel free to switch out ie for lord dom
Frightning1 votes
, and is pretty much core on 
. After that, imo, go with, , 
, situation 6th item (old GA was an option). I find that once you have enough AS, it's more valuable to start stacking AD so that your autos, Qs, and E do more damage (her E basically functions like a huge AD steroid for her basic attacks so long as you actually manage to pop it before dying/killing them). With a similar build to the above back in season 5, I managed to repeatedly outduel a full-build 
because I could Q(hop into range)+AA(no hop)+AA(no hop)+E 100-0 her before she could get off her 3rd AA and collect her Silver Bolts (W) proc.
DemainaNyx1 voteshttp://champion.gg/champion/kalista/ADC http://www.probuilds.net/champions/details/Kalista
Try checking these sites or others when creating a build. They are least give you an idea of what is good or at least what others think are good.
All Kalista wants is to Rend people. She wants to stack as many spears into people as quickly as possible and rend them. So, attack speed is key on her. Blade of the Ruined King is perfect cause it offers attack speed and percent health to help to make up for the 90% basic attack damage she gets. Runaan's just means more spears in more targets. Other than that, it's all situational.
Considering Kalista wants long drawn out fights, lifesteal helps her with that. Plus she needs to hop around to avoid skills due to shorter range, so Mecurial is really good cause it gives you a get out of jail free card. Phantom Dancer is also another good choice cause it gives her some survivability due to the damage reduction.
