Hi, i'm Merxen and welcome to my guide to item building as Vi, also a few attack combos to put up some nice burst damage. This is my first guide and i have only read a few things on how to add links to the items, your opinions are welcome in the comment section.

You know the routine. Hunter's Machete and 5 Health Potion
When you aquire enough gold, purchase Spirit Stone
Now after that, you should go for Sheen. Now, you shouldn't work on getting Trinity Force, first you should upgrade your Spirit Stone to Spirit of the Elder Lizard. But before that, you might want some movement speed to catch up on the creeps around the jungle. So buy Boots, but first upgrade them when you feel it's neccersery. Now you should start building up to Triforce, and when you finally get it. Starting saving up for Tiamat
and end up with a Ravenous Hydra later. Now you got some lifesteal, but you might want some more lifesteal and attack speed. So build up for Blade of the Ruined King. Survivability? save up for Guardian Angel and you should be fine. During lategame (35-45 mins ingame) Spirit of the Elder Lizard is kinda useless, so you could sell it and save up for Bloodthirster or buy Spirit Visage to boost your health and the hp you get from lifesteal. The 400 health increase also works well with her passive Blast Shield.
All in all, you should have this by endgame:
Ravenous Hydra Spirit of the Elder Lizard Blade of the Ruined King Trinity Force Mobility Boots and Guardian Angel

At the start of the match, you should either pick Denting Blows or Relentless Force, my own prefference is Relentless Force. After you did that, you should max out Relentless Force and Vault Breaker. Why? because both of them deals some nice damage. When you get 2 stacks of Denting Blows on a target, use your Relentless Force. It will do extra damage due to the way Denting Blows works. Also if you got Trinity Force, you'd see some nice damage. Time for some combos. When engaging with Vault Breaker, it procs a stack of Denting Blows, then activate Blade of the Ruined King and basic attack once, then use your Relentless Force so your target will have lowered armor. Then your target would usually attempt to flash and flee due to the high damage you're dealing. You should totally chase them down with Cease and Desist, they wouldn't stand a chance.