How to find the center of an object
Sometimes you need to find the center of an object. For example, you may be drawing things orbiting around something else. In any case, finding the center of an object is pretty easy to do freehand.
To find the center of a square or rectangle, just connect the corners diagonally, making an X through the box. The spot where the lines meet is the center of the rectangle.
Finding the center of a circle is done similarly. Draw a straight line from the topmost point to the bottommost point, and another line from the leftmost point to the rightmost point. This should form a plus, and like the rectangles above, the center of the plus is the center of the circle. Of course, if you've drawn the circle according to my tutorial the plus is there already.
But what if the object isn't a rectangle or a circle? In this case, draw a bounding box around it to find the center. If you only need to find the center of part an object, just place a bounding box around that portion.