One thing to note is that the D3200 has permanent focus priority, meaning that the camera will not take a picture unless it thinks it is in focus. However, what it thinks should be in focus may not be what you want it to focus on. A problem can sometimes arise if you use the traditional AF focus method of using the central focus point and recompose the picture without keeping the shutter button half-pressed. If you do this and the central point now falls on something a different distance away than the subject, the camera will refocus. Your picture may then look out of focus but, in fact, the camera has just refocussed on something else, often in the background.
Worse still, even if you do keep the button half-pressed, the camera may not take a picture at all if it thinks the focus is not correct after you recompose. This happens to me with my D3100 quite often if, for example, I want a subject close to me to be situated far to one side of the frame beyound the focus points. Because no focus point is on the subject after I recompose, the camera isn't happy to take the picture the way I want it to because of the focus priority feature. Very often the camera will not take a picture if there is nothing to focus on under the central focus point - like a traditional British grey sky with no contrast it it