The usual capsule advice is to buy less and buy better, which is true and completely unactionable. The useful version is structural: pick four pieces that each do a different job, and make sure any two of them work together.
The four jobs
One heavy layer. This is the piece that carries an outfit in cold weather and needs to look intentional on its own. A 450gsm pigment-dyed hood or a terry field jacket. Buy this one oversized, because it goes over everything else.
One midweight crew. The workhorse. 330 to 350gsm, no hood, so it layers under the heavy piece without bulking at the neck. This is where a graphic earns its place, because it is the layer people actually see.
One quiet piece. Solid colour, minimal or no branding. Its job is to let the other three be loud. Most capsules fail here: people buy four statement pieces and can only wear one at a time.
One wildcard. The piece with the print, the unusual colour, the thing you bought because you liked it. A capsule with no wildcard is a uniform, and you will stop wearing it.
Why any two have to work
Four pieces give you six possible pairings. If two of your four clash, you lose a third of your combinations instantly. So the test when adding a piece is not whether you like it, it is whether it works with all three of the others.
In practice that means agreeing on a base. Pick either warm neutrals (cream, elm, brown, burgundy) or cool ones (black, navy, grey, washed indigo), and keep the quiet piece and the heavy layer inside it. The wildcard is allowed to break the rule. Nothing else is.
Match the weights, not just the colours
A 450gsm hood will not sit over a chunky 400gsm crew without looking like a duvet. If your heavy layer is genuinely heavy, keep the layer beneath it at 330gsm or lower. The inverse also holds: a light outer layer over a heavy crew reads as an afterthought.
Fit is the whole thing
Oversized over oversized is a silhouette with no shape. Pick one axis of volume and hold the other steady. If the hood is boxy, the crew underneath should be closer to true to size. Most of our oversized pieces are cut a full size up, so size down if you want a regular fit.
Get those four right and ten outfits is conservative. The point of a capsule is not owning less. It is that nothing you own is stranded.