How do you know it is 11-12? Did you get it done with calipers? Just curious.
You may need to between 6-9 to start seeing the abs. Ask the other guys about it that do have abs showing where they are at. Maybe Goose will know or check over at the
http://www.abcbodybuilding.com boards.
Eating junk versus eating healthy food makes a difference. Sugar and Sat. fat will not help to get you the 6 pack. Chances are you still have some fat deposits on top of the muscle that you can get rid of by changing up your diet AND you will get better muscle growth if you feed that muscle the right foods as well. Lean protein is your friend.... cottage cheese, egg whites, whey protein, lean meats. Healthy fats next - natural peanut butter, extra virgin olive oil, Udo's blended oil, salmon, tuna, flax. Complex Carbs - Rich green Veggies, Sweet Potato and other good carbs like berries that have a natural thermogenic effect like blueberries, strawberries. Stay away from the simple carbs unless it is immediately post workout.
Most bodybuilders hate the word "tone".. you want muscle definition and muscle growth. To get that you need to eat healthy, challenge your muscles with lifting heavy - giving them resistance - tear, rebuild, rest, repeat. The cardio also helps with reducing fat but don't overdo it to the point you are burning muscle. There really isn't a whole lot of magic to it. Sometimes it is just genetic too.
Post your workout routine, how often you do it, how much time you have to workout, and the resources you have available (gym, home free weights, etc) and what you enjoy doing. If you want, I can make some suggestions for you to try or point you in the direction of some web sites that might help. How long have you been working out regularly and consistently?