A wardrobe check-list from Real Simple (I’ve edited the list just a tad):

• Tank – black, built-in bra, ribbed cotton [mid butt length. Variety of flattering colours]
• White and Black T-shirts – short and long-sleeved
• Black Turtleneck
• White button-down shirt – white, other colours
• Crisp white blouse
• Crewneck sweater
• Cardigan
• Black Dress [day to night]
• Pencil Skirt
• Jeans
• Classic Black pants
• Skinny jeans [or slim]
• Khaki pants
• Denim Jacket [doesn’t have to be denim]
• Cropped Jacket
• Black Cashmere Wrap
• Ballet Flats
• Basic black pumps
• Metallic evening shoes.

Plus seasonal essentials (I culled their list):

• Flat boots (black or brown)
• Sweater – heavy (winter) [not essential], lightweight (spring)
• Wool trousers
• Winter coat
• Pantsuit [not essential]
• Dark-wash jeans
• Cashmere hoodie
• Gray flannel pants
• Down vest
• Cotton blouse
• Printed tops
• Waterproof raincoat
• Dress – cotton printed, strapless
• Shorts – khaki [at least 4 inches long]
• White jeans [not essential]
• Flat leather sandals
• Cotton drawstring pants
• Chinos
• Capri pants
• One-button blazer
• Cotton polo

I don’t agree with some things in this list at all. However it is a useful starting point.

I would have to add:

• Cami – to go under see-through tops
• Hat
• Sunglasses – black, brown
• Scarves – long, short
• Handbags – one summer day, one winter day, one evening
• Trainers
• Belts – black, brown
• And one drop dead gorgeous dress/outfit for surprise evening where you get whisked off to the opera in a private jet.