Varying Edges

Make sure to vary the hardness and softness of your edges when texturing.

Smooth transition, not very convincing. Looks like a soft bulge and there is no clarity of the volume.

Hard line, dark meets directly with the light. Implies a crease of some sort. Sharp edge.

Rounded edge. Implies round edge with a crease-like intersection at the bottom.

There are a lot more than these three and you can do averages between them. Try to get more than just soft transitions in your textures.