When developing a Capsule wardrobe I found it helpful to have some very simple, easy guidelines, or it just became overwhelming. Here's what worked for me...
Winter capsule wardrobe:
Choose just 1 neutral colour - black, brown, stone/taupe, or grey,
Workwear in neutral colour:
3 bottoms (skirts or trousers) 1 top and 1 piece of knitwear or jacket. 1 pair of shoes, 1 pair of boots, one handbag, 1 smart coat.
Loungewear in neutral colour: 2 bottoms (I ditched jeans - never really felt comfortable in them). 1 top, casual shoes.
Evening/smart work /interview: 1 dress in the neutral colour.
Choose just two accent colours - those that will often crop up in winter that suit you and will go with the neutral. - eg: white or cream, red, purple, pinks coral, deep or bright blues. Try to pick 2 colours that will work together.
Workwear in accents: 4 tops - long or short sleeved. Stick to plain or an unobtrusive pattern as it is less likely to look dated over time. Jewellery, scarves if you wear them and they suit you.
Lounge wear: 2 tops in accent colours. Jewellery/scarves, hat, gloves, perhaps an extra informal bag in accent colour. Informal coat in accent colour.
All of these will items will work together and are sufficient for a varied wardrobe for each week.
Once winter is done - pack up all the clothes and accessories in plastic storage containers and switch to a summer capsule wardrobe.
Summer capsule wardrobe:
Choose just 1 neutral for summer - navy, camel, olive, stone/taupe, or silver-grey, These colours tend to reappear every spring/summer in some form.
Again choose just 2 accent colours (different to your winter ones) - such as green, turquoise, cream/white, pink/peach, yellow.
Follow the same principles as the winter wardrobe, but substitute items as needed - sandals instead of boots, summer dress instead of smart neutral one etc.
Each season check your capsule wardrobe for items that need replacing. You'll be shopping for just 3 colours - 1 neutral and 2 accents; and every item will work with the rest of the season's wardrobe. Take your time and choose items carefully over several seasons to build it.