Off white for base, full white for shine, a darker off white or a light pastel color for the shadows

Use a light shade of blue or purple Ir any other color as long as it's a very light shade Experiment and go with what you like best

blue or any cold colour

Eaat My only advice is don’t use a flat grey, keep them warm and cool toned Shading looks nice when inside the main shadows you have like warmer as the normal then inside there’s the same value but cool toned