Well big scarves are in and as it is getting very cold I would buy a massive tartan cashmere scarf with green in it. Then buy some gloves and a hat in a plain colour that picks out the colour in the tartan. For instance Green coat, green, red and grey tartan scarf and grey hat and gloves.
Massive scarves are 'IN' . As you have a plain Green coat a pattern scarf will compliment it.