I'm trying to model a bird and I'm having a lot of trouble when I try to align correctly the right eye with the left using the mirror modifier. I use the option in the menu: Object> Transform> Origin to 3D cursor to accomplish the task. But before to do it, I try to put the cursor in the middle of the head. The problem is that this type of alignment is not careful. It seems to be aligned on the X axis but not on the Y axis. Do you know a more precise way to do it? Check the screenshot attached.
I tried to use the method used here: duplicate questions ?. I tried to put the object origin several times on the center of the body while I'm in edit mode and then I did Ctrl+Alt+Shift+C but I'm not accurate when I place the cursor and to make it works it needs a lot of time and patience. Is there a faster way? Check here: