Learning to remove covers can help tremendously in diagnostics. Just as one of the first tools you reach for when performing clinical diagnosis is the X-ray, so too should you look inside a device that you need to trouble-shoot.
Learn how to take the covers off of your equipment, especially the sterilizer. Many times I've had people tell me that they've "got a leak in the back left corner" of their sterilizer so they want to know what is in that corner. The reality is often that the corner in question is simply a low spot and that's where the water runs. To find the actual source of the leak, your best bet is to remove the cover and run a cycle again. With the cover off of your sterilizer, you can see what's actually going on and may be able to better pinpoint the source of trouble.
The same can be said for all of your equipment. Taking the cover off of a delivery system will help you identify the source of a leak there, as well.
Of course, taking the cover off can be the first step in solving a wide range of issues, not just leaks. A visual inspection is often the best first step in narrowing down a wide range of problems.