First and foremost one has to know the domain, what are the things that tend to go wrong. And this is platform specific knowledge.<p>I mean, you&#x27;re testing a web app? Disable JavaScript in the browser.<p>Testing an Android app? Rotate the phone to change screen orientation, especially when there&#x27;s a background operation going on - that&#x27;s a typical spot for bugs, but no amount of general manual testing know-how will tell you that. And so on