First thing: after you drop the hair from the browser onto your figure, double click the hair “model” to open it in the vertix room. select the entire mesh and add 1 level of smoothing. This will help to soften any “hard” polygons.
in the Assembly room go: EDIT—> Remove Unused Masters—> Consolidate Duplicate Shaders… This will reduce the instances of shaders, since it’s an automated process it might miss some or there may be reasons why you want several instances of the same shader (for editing later…)
in the Shader Room, make sure any image texture is at the top of the Color Channel. The translation from Poser sometimes multiplies the image map with grey when translating Poser’s lighting info - there is no equivalent light/shader function in Carrara. A grey multiplier takes away detail in Carrara, but it is possible to change a color this way, so if the image map is mixed with a color it may be intentional… You can also tint (usually darken) a Poser hair shader this way.
Last shader trick is the one most people miss, but imo is what kills prop hair in Carrara. Change the Translucency Channel to a color, usually very dark and unsaturated. This allows back lighting to brighten thin hair strands, but more importantly it softens the shadows. Most hair props are several “leaves” or “plates” of polygons with alpha map transparency layered to give depth. Carrara’s shadows are too strong in this case and each poly layer can end up casting a dark shadow on the layer beneath, making the polygon structure of the hair very obvious. Adding a bit of translucency allows more light to pass to the next layer, even to the forehead, which helps hair look more natural with the light-bending properties of fine hair. No matter the hair color I’ve found it looks best with a dark brown translucency.