How do I stop missing duplicate invoices and approvals?

You process the invoices, but the ones you should have caught, the missing approval, the duplicate, slip through. That is not carelessness so much as speed without a net. When you rely on catching things by eye while moving fast, some will always get past you. That is how attention works. The answer is not to try harder or stare longer. It is to build a small, fixed check that runs every time, so catching mistakes does not depend on your focus that day. A checklist does what willpower cannot; it stays consistent when you are tired, busy, or distracted. Write a short list of the few things you verify before any invoice is paid: right approval, not a duplicate, matches the order, correct amount. Run it every single time, no exceptions. It will feel slow for a week and then it will just be how you work, and the misses will quietly disappear.