I have reviewed portfolios as a hiring manager for six years. The uncomfortable truth is that a first pass takes about ninety seconds per case, and most cases lose the reader in the first fifteen.
They lose them the same way every time: four paragraphs of context before anything happens.
Lead with the decision, not the brief
The reader does not need the company history. They need to know what the problem was and what you decided. Put that in the first two sentences.
Checkout abandonment sat at 71 per cent on mobile. We suspected the address form. It was the shipping estimate, which only appeared after the address was entered.
Now the reader wants the rest. That is the whole job of the opening.
Show the version that did not work
A case that goes straight from problem to polished solution reads as a story about a genius. A case with a discarded direction reads as a story about a designer. The second is more convincing and considerably rarer.
One paragraph and one image is enough: here is what we tried, here is why we dropped it.
Numbers, with the caveats attached
If you have a result, give it with its context: what moved, over what period, and what else changed at the same time. A designer who says conversion rose four points, while noting that a pricing change shipped the same quarter, is more trustworthy than one who claims all of it.
If you do not have numbers, say what you would have measured. That answer is fine. Pretending to numbers you do not have is not.
Length
Three to five screens. Anything longer will not be read on the first pass, and the first pass is the one that decides.
The part people skip
Write what you would do next. Every real project ships unfinished, and naming the thing you would fix first is the clearest signal that you understand your own work. It is the last paragraph of the strongest cases I have read, and it takes ten minutes to write.