often in the corners there is more than one support beam so the 16" does not start at the corner.

Also, it could have started from the opposite corner. Very commonly the last stud in a wall might only be 8 or 10 inches or whatever from the corner because they started at the opposite wall.

Also, sometimes there's a window or door or something that causes there to be a support beam in a place that throws off the 16" from the wall. So, you just need to find one in the middle of the wall. and then go 16" from there.

Also, older construction sometimes had studs at 24".

If you're going to use nails to find it, then I recommend getting a very thin nail and then trying to locate the stud with as little damage as possible. If the wall is white or off white you can use toothpast to fill in the small holes. However, getting a stud finder is the best way and they are cheap.