Response time. The lower the response time is, the smoother the camera movements will be. On the other hand, a high response time will lead to motion blur since pixels don’t have enough time to switch between colors during fast camera movement. Which to choose depends entirely on whether you prefer. Check it yourself.
Screen Size. Size doesn’t matter that much. Gaming monitors are usually between 21 inches and 27 inches since those represent the perfect balance of visual clarity and viewing comfort.
A modern gaming monitor has the following inputs and outputs:
-5mm Audio Out
Apart from those, a monitor may also have a 3.5mm audio input and one or several USB ports of varying types.