Concentrating on performing each repetition of each exercise with superior form and timing will separate you from those who do hundreds of sit-ups and get no results. The training is arduous, but if six-packs were easy to attain, wouldn’t everyone have a set?
Following the guidelines described above will put you well on your way towards the six-pack you desire. They’re not easy principles to follow at first, but you'll become more comfortable with them in time. Stick to it, and before you know it you’ll proudly displaying the prize you've earned through all of your hard work.
As a final note, be sure to check with your physician before making any major changes to your diet, or before beginning a new exercise program. Good luck, and enjoy your new set of six-pack abs!