I always knew Vitriol was a good Striker. It was not until much later that I discovered her ability to mess someone up. It is not uncommon for Alchemists to have 3 damage results in their playbook, but few have the ability to buff both their TAC and Damage. This is where she starts to get interesting.
As I mentioned in my Flask article, he is her little buddy. It is also good to remember that her abilities are triggered by the opponent being in cover and there is cover in many places. I have had a few occasions where I was worried about getting flask in there then realized we were next to a wall anyway. It is good to have some crowding out going as well.
Her next best buddy is Decimate. I actually learned this combo on accident one game when I stole Thousand Cuts with Midas tossed it on a model near Vitriol with nothing better to do. It turns out that -2 Def on a 4+/5+ Def model with no armor makes them quite squishy. Most models with those defense stats can be easily taken out by Vitriol in one activation in the right circumstance. Because of this, Decimate has all but solidified her spot on my team.
Overall, this puts Vitriol in the role of a goal scorer with the ability to take at least one model out as well. Although I generally start her and Mist together, the generally each head in separate ways to increase threat vectors. You should always look ahead to decide if she needs to be a baller or a thug that turn. Either way, she can generally spend 4 Influence without regret. The key for maximizing her use is to remember that even though she can self buff with smoke cloud, try to have someone else do it first.