When the neck is convex or back bowed, the action must be raised to keep the string's proximity acceptable in the central part of the fret board. This misalignment can make the action height higher up the finger board unplayably high. Potential action problems are myriad, but I've covered the most common, so I will move on to body noise and loose parts. Most of these sounds can be located externally by using your hand to dampen a loose part. You should always check the simplest potential problems first, like a loose tuning machine screw, or even a string end vibrating against the guitar.
Truss rods can make interesting buzzing noises also.
Fortunately, a syringe injection of glue puts a quick end to the raucous tones. The internal joint failures are more directly diagnosed. You simply use your knuckles or fingers and tap the top and back plates listening for vibrations or rattles. Braces attached cross grain to a back or top are the must likely to come loose. This is because the lateral expansion and contraction of these surfaces cause great stress on the glue joints between the back or top and the brace.