I see 0 Vi games, but w.e
For starters: Vi is a champion similar to
. What this means is if Renekton doesn't shit on lane, then he doesn't have a late game. Even then, he''ll still lose if the game goes on too long.
So, with Vi you basically play her in jungle as early game cheesy asshole. You have access to a long range gap closer that can bypass wards similar to
and you use this to your advantage. You want to gank from these awkward angles unless they are not needed, and you want to particularly prey on champs with few escape abilities/lanes with high CC.

Your best ganks are 3-11.
Level 6 is when you can make really strong picks. You typically want to camp winning lanes, or lanes that have the potential to hard carry.
During team fights, you pretty much press R on the adc, or mid laner and proceed to make their life a living hell.