Basically you have to do 3 things:
1)Low fat, low calorie diet
2)Burn fat(especiallycardio exercises like running and jump rope)
3)Exercise
Apparently the first 2 are MUCH more important than the third.
You could do a billion crunches a day and you'll never see your
abs if there's fat covering your abs.
It's more about body fat reduction than how many ab crunches
you do per day. Cardio burns lots of calories and thus, burns off excess fat. You don't even need to go to a gym.
My cousin runs 5 miles per day. She doesn't do any other exercise and
her mom cooks her nutritionally balanced meals every day. She never goes to the gym or lifts any weights. Her abs(and the rest of her body

) are incredible.
For a good plan to get into running, go here:
http://www.coolrunning.com/engine/2/2_3/181.shtml
Run 3 days a week(for ex, Mon, Wed, Fri). Jump rope on the other 3 days (for ex. Tues, Thu, Sat). Rest on the 7th day(for ex. Sunday).
That's all.