Now, everyone have different types and textures of hair. The important thing to know, first hand, is that these products will not create curls that do not exist. Let's say your hair type is more of a zig-zag look, these products will not make it into a s-curl look. The purpose of these curl defining products is to clump your coils or curls together. Some people might have to twist their hair to create more curly hair look.
For me, different products clump my hair strands differently.
For example, the picture below, shows how my hair clumps together with Tresemme Natural Conditioner left in.
Here is the same area of hair after Generic Paul Mitchell Leave In Conditioner and Eco Styler Gel (Krystal) has been applied.
This is the same hair with Generic Paul Mitchell Leave in Conditioner and Shea Moisture Curl Enhancing Smoothie
What product(s) do you use to "clump" your hair?