Everyone has an 8 pack, however most people do not have low enough body fat to see it.
-To see your six pack, first concentrate on lowering your body fat percentage. When you have a low body fat % naturally your abdominal muscles will look more defined. Losing weight is not the same as losing body fat. Weight can be lean tissue or adipose/fat tissue keep that in mind.
-Abdominal exercises may make those muscles stronger. However you probably will not see defined abs unless you have a low body fat percentage. Some people do hardly any abdominal exercises, but have defined abs as they lift weights and keep a low body fat.
-Eat a clean diet if possible. Higher in Fruits, Vegetables, and 100% whole grain. Moderate in lean meats,and dairy. Drink copious water through out the day. Stay away from junk as much as possible.
-Get more sleep as this can increase testosterone, and HGH to a degree which will aid in keeping your body fat low.
If you are under age 25 getting a six pack may be easier, as you still have ample hormones in your system to help lower body fat, and promote development. After age 30 you will not have as many hormones in your system naturally however you can optimize the hormones you have with healthy lifestyle.
-*Aim for defined abs, the six pack may be overrated. If your abdominal muscles are well defined that is good.
Genetics can be turned off, or on. It maybe difficult to get a six pack, but it is possible. Do your ancestors, or anyone in your family have defined abs.