You need to diet even more then. Getting a visable or kick ass 6 pack takes dedication to diet, supplementation, and cardio.
The visibility of your abs is directly related to your bodyfat percentage and size of your ab muscles.
Theres a few supplements you could take to help with your diet, cardio, and training and acheive a 6 pack.
Are you taking an ECA stack at the moment? If not, why not? Are you alergic to it? If so, how much are you taking? How often, etc?
How often are you eating? 5 or 6 times a day? 3?
Whats your caloric intake looking like?
What kind of diet are you on? Isocaloric? Hi protein, hi fat, low carb?
Doing any cardio? If so how often, how long, what heart rate are you trying to maintain?
Supplement X isnt really important until you have all of the above lined out. Then you pick the supplements that meet your needs, plan those supplements into your diet, and shoot for it.