Monochrome or tonal blues, including some pattern (winter edition)
Outfit ideas...Crinkle skirt with Polo sweater. Dark denim, gilet, bright blue blouse. Wide leg pants, slim top, moto. Look for richer textural differences. If the pieces match perfectly, then try to add just one other colour (for accessories) and if it feels too stuffy, mis match the formality level. Also vary textures as dramatically as possible.