When playing Vivian note that you can cancel your shield, I see lower level players keep it up when they aren't using it which means they have to wait longer to be able to use it again.

Buy "illuminate" from the item shop (at least to level 2 if your struggling against her), she will never think twice to go for you again as you will see her coming from a mile away!

When terminus uses his ult to get back alive, use reversal. If you time this ability right, you can fire over 3000 damage towards terminus and let your teammates or yourself finish him off.

Vivian's shield only protects in front of her, use a flank champion such as Skye to attack her from behind. With any champion you should still try to attack her if doesn't notice you.