the creases and texture of the dress are not visible
If you want to emphasize folds and texture, you need shadows. Think about a brick wall -- if you shoot it with very soft light, or with light coming from the direction of the camera, the wall will look very flat. If you shoot it with very directional light coming from the side, every little bump on the wall will create a shadow, so that the texture of the wall is visible.
It's the same idea with clothing. You some contrast between the peaks and valleys of the folds, but you probably don't want hard shadows. So you want light that's directional, so you get some texture, but soft, so that transitions between brighter and darker areas are gentle. Soft light comes from large light sources, like a softbox, an umbrella, or even just flash bounced off a wall or ceiling.
In short, it sounds like the problem in your shots has a lot to do with the lighting that you used. If you post some example shots, I'm sure folks here would be happy to give you more specific advice.