Ok, you need to know something before we can really answer that. Having a visible 6 pack is all about body fat. You can have the biggest muscles in the world, but no one will see them if you have too much body fat. The general rule of thumb is that you need to be at or below 10% bodyfat before you can see your abs. This is different for different people, because people carry body fat differently. Someone who carries less fat in their abs could carry more bodyfat while still having visible abs, but someone who carries more fat in their abs may have to be will into single digit bodyfat numbers before they will have well defined abs.
Do you know what your bodyfat % is? If you don't, then feel free to post a pic of yourself shirtless and we'll be able to give you a good estimate, which will let you have an idea of how much fat you'll have to lose before you'll have visible abs.
As for actually working your abs, honestly, it's not as important as people make it. The muscular makeup of the abs and calves makes it very hard to make them grow at all, but that same muscular makeup allows you to work them with a much higher volume and frequency if you want to. I'd say you can work your abs every other day if that's what you want, but if it's all about getting visible abs, that's not nearly as important as getting your bodyfat % down.
Current PRs at 242, raw w/ wraps- 525, 355, 605, 1485
Roboro tui, perimo vester adversarius
(Build yourself, destroy your enemy)