Get six pack abs by learning from others who have achieved this goal before you. This is how you wil know what you are doing and be able to do it more effectively.
To get great abs you should start doing effective ab exercises. Stop doing basic crunches on the floor.
Some great exercises that will really help your gains include hanging knee raises, exercise ball sit ups, and reverse crunches.
These will really help sculpt out a leaner mid section and build muscle. Also eat right.
You do not want to have junk food all the time. Instead eat natural foods like beans, nuts, and fruits.