We can't help if you don't know what to look for in the first place. These are double dies and what a DDO/DDR should look like. click on the different class. http://doubleddie.com/58222.html This is worthless doubling. It is the most common type of doubling and usually what are found. http://doubleddie.com/144801.html
those are not die markers, they are die cracks, and can be found in that same area on thousands of coins but they may not be all exactly the same, and just because a doubled die coin happen to have cracks in that same area does not mean all coins with those cracks are doubled die...