A customer picks up one slipper. A shelf, however, is read as a single picture — and a shelf made of six unrelated slippers reads as a jumble, no matter how good each one is.

Start from the number of soles, not the number of styles

The cheapest way to widen a range is to keep the sole and change the upper. Two sole constructions can carry six styles, and every construction you add costs tooling, bonding setup and a separate set of quality checks.

Colour carries the range

• Pick the colour palette before the styles, not after.
• Repeat at least one colour across two constructions so the shelf ties together.
• Hold a physical swatch for every colour — screen renders lie.

Leave one obvious entry price

Every range needs one style a customer can buy without thinking. If the cheapest item is only slightly cheaper than the next one up, nothing is anchoring the shelf.