The lesson
Write the case-study headline as the customer's outcome and timeframe, then give the three results as a checklist before the story starts.
The headline is 'How Houdini lifted conversion 88% with a three-month Shopify relaunch'. After a single photo of a runner and a short intro, a ticked three-item list gives the results. The body runs 'The challenge: a site built for show', 'The solution: one platform a lean team could run', and 'The result: less maintenance, more time to sell', with two pull quotes.
Don't copy the 88% or the Houdini details. Only headline a result you can source from the customer. Keep the outcome-first title and an early results list.