6 packs aren't made in the gym...
They're made in the kitchen.
Take a look at the Abercrombie and Fich model guys - they all have six packs, but muscle-wise, they don't look like they could pick up a wet towel without grunting. So they're obviously not going to the gym. They're getting it by starving themselves.
If you are seeing a blurry four pack, then you are on the right track. You just need to tighten up your diet a bit more - get 500 cals below maintenance and stay there every day for a few weeks. Don't make the classic mistake of binging one day a week and ruining your progress.
Also, if you drink, cut out alcohol - this will bloat you and make abs less visible.
Check out your sodium levels too - high levels of sodium will make you retain more water and blur those lines up.
My final tip should go without saying, but some people may not have heard it before. If you don't drink enough water, then your body will try to store as much water as it can - usually in or around adipose tissue.
So if you're not drinking about a gallon a day, then your body is storing a lot of water weight. Crank up the amount of water you drink, and over a week or two, your body will relax its deathgrip on water resources. It will start using more as well - you may notice yourself sweating more, and you will definitely be going to the bathroom more.