Now for an engineer like myself it's not very difficult. I look at the inventory, the assembly line, and talk to the people. For you, a non-techie, you kind of have to trust me. So here's what you need to hear.
Any business needs a clean and ordered general office. Good people like clean and order. The same goes for the production area.
Look for minimum distances the production need between operations. Carrying things around means something gets dirty, people get in the way of others and things need to be counted multiple times.
Is the machinery clean and well tended? Expensive machinery breaking down is not a good way to profits. Clean machinery last longer, is lubricated regularly, and of course, is cleaned top to bottom on a rigid schedule.
Is spaced just wasted in the production layout? Are machines too close for safe movement but not to far to wast space? If the spacing is correct the production people will look relaxed and ready for the next activity. In fact, ask the production people if things are OK. Ask them if they like working there - I always do. A good company's manager won't mind you asking. Ask them if enough of the correct machinery is available. What could be added? What is the % utilization of current equipment? Theproduction area, your clue to profitability.
Look at inventory, both raw inventory and finshed goods. Are things finadable? Countable? Look good? Maybe everything has a barcode label. Has shelf space been left for expansion? How much space is needed for the sales volume you want for your investment to pay off? You don't want inventory to be over-stuffed on the shelves.
And are you comfortable in the production area - really.