If the snow in your photos is grey then you should overexpose a little, or wait for the sun to shine; snow can look blue in shadow areas or if there is a lot of blue sky, if you don’t like this effect try to take photos when the sun is lower in the sky or compose photos with less dominant shadow areas. Foreground is important in landscape photography. If the foreground is dominated by snow it is important to look for textures and shapes within the snow. Avoid including large, plain white areas. Snow photos can work well in cloudy or sunny conditions but sunshine will help to bring out textures in the snow and make the sky more dramatic; I tend to find that woodland snow scenes are best when it is cloudy.
It’s important to expose the photos carefully so that the snow is bright but not over-exposed; when taking the photos you should review your images and look for highlights (most cameras can be set to show over-exposed areas; see your camera’s manual).