?Maintain a wholesome, healthy diet and keep well hydrated w/ high quality filtered water. Unless you get these two paramount habits working for you it is difficult to impossible to loose body fat and/or gain lean muscle mass. If you are looking to improve your abdominal definition reducing overall body fat and increasing the size of the abdominal muscles is the only way to succeed. You CANNOT spot reduce! This means that all the abdominal exercises and ab gizmos in the world won't develop your abs unless you have an integrated, intense approach to doing so.
?Use Free Weight and Core Exercises! You need to gain functional abdominal strength as well as do exercises that attempt to isolate the abs if your goal is to have an athletic looking midsection. If you want an eight pack you need to incorporate core exercises, stability ball training and perform power strength training movements like squats, deadlifts, lunges and rows.
?Work ?em Hard. I recommend doing intense abdominal isolation training at the end of or workout. Training them hard at the beginning of a workout could leave you more susceptible to injury as they are very important, much used stabilizers. To make improvements on your goals to having ripped abs use high intensity exercises like stability ball crunches with a weight on your chest or extended over your head. Use a resistance that limits you to 8 - 12 reps, build up to 3- 5 sets and allow for total recovery before working them in concentrated isolation again.