It is not that difficult as other directors do it well. I see that in Japanese shows. It is OK if actors pretend to eat or drink when it is believable. In many episodes of Seinfeld we see the actors drinking coffee but we can clearly see that they weren’t taking a sip.
Revenue doesn’t equal profit but many companies are using multiple schemes to show that they are not profitable. So we also need to check the revenue. A company can just increase the CEO salary to eat up all the profit.