How can I get well defined six pack abs?

crunches, lots of them. Push ups help too. Good luck!

do crunches, push ups, id say 100 crunches a day and 30 push ups a day, and lay flat on your back hands to your side, and just lift your legs, do about 10 of those. do this once a day and im almost positive within 3 months you will have those abs

Seeing as how you’re already almost there, congrats. It’s tough for most people to get even that far.

Now you sound like a “skinny” type of person so correct me if I’m wrong. What you should do is add another 300-500 calories to your diet as your high metabolism is holding back your muscles development.

If you’re not a skinny person, forget all that. What you need to do is forget about crunches. Stop doing them all together in fact as crunches are one of the crappiest ab exercises. What you should be doing is adding weight and resistance to your ab routines.

For instance, the pulley crunch is a great weight exercise.(http://www.youtube.com/watch?v=5nDGiMYmbR0)
Granted, it’s basically a crunch just in a different position, but it has resistance added to it.

You need resistance and weight so your abs actually become larger. The other thing you should be doing is doing more exercises to attack every part of your abs. Check out a pretty killer routine to do just that http://rippedbiceps.com/abs-work

Finally, think outside the box. There’s a program called the truth about six pack abs that details more outside the box exercises. Have you ever thought about doing front squats to build abs? Probably not, but they’re great because they force your ab and core muscles into overdrive as they try to stabilize you.
http://rippedbiceps.com/6packabs