Working on the abs requires working on various muscles in the abdominal region. This is one of the reasons why solely doing sit-ups won't help. Another reason is that you need diet, cardio, and strength training to build better abs, but that is a topic for another day.
For today, we'll focus on one of the large muscle groups in that region: the obliques (sides of the abs). You can work these by doing a variety of exercises, but one of the really good ones is called the "Russian Twist".
I will show you two ways to do this exercise: the easier and the more challenging way.
Keeping the heels on the floor and the upper body angled back, slowly twist side to side. This twisting motion should come from the waist, not the neck or the hips. Looking in the direction you are twisting towards sometimes helps with this movement.
More challenging way
To challenge your body, do the same exercise with your heels lifted off the floor. However, try to keep the torso in the same position and still twist side to side from the waist, not the legs. Be slow and precise with your movements.
Cheers Eights & Weights!