Since I'm not working under standard conditions, I shouldn't be using Idea Gas Law.
Accuracy of ideal gas law is not a matter of using it at standard conditions. Depending on the accuracy required you may already need corrections at STP.
To adjust for real gas, I have to use the VDW equation.
Yes and no. Whether you need a better formula than the ideal gas equation depends on the accuracy required and the conditions. Yes, sometimes VdW equation will give better results, but sometimes using it is just making life harder without any benefits.