There are a couple of different reasons you may be getting tool marks and nicks on your wire and rings. Firstly, it could be that you are transferring marks that are already on your pliers. Check the inside jaws for smoothness. I use a nail board to keep mine smooth. I don’t buff them with the finest side of the nail board as tools that have a really shiny surface can slip on the wire more easily. Don’t try this for the first time on your really expensive pliers, get used to modifying your pliers with a cheaper pair.

The sides of your pliers can also mark wire and rings if they have a sharp edge. I slightly round the sharp flat edges of my pliers on the sides and the front so that the sharp angle of the edges is smooth and doesn’t close directly onto the wire. A bit like how a chasing hammer with a rounded face doesn’t have the edge hitting the wire. Again try this for the first time on cheaper pliers, a little at a time. A nail board or sanding stick will give you a consistent angle in filing.