Part One: Strategy · Deciding what to build
Cutting scope is how work gets finished. Cut the wrong way, it leaves half of a big thing, and people can only use a whole thing, however small.
Time runs short and something has to go. The usual cut is by layers. Build all the screens but not the saving. Build the data import and leave the pages that show it for later. Ship the report designer without printing or export. Each piece is a slice of the grand plan, and none of them is any use. The area manager of a restaurant group cannot do anything with a report she can design and not print.
In a large company the layered cut often comes from the org chart, with each team shipping its own layer on its own schedule. One person does it too, by drawing every screen before any of them saves.
The other way to cut is by breadth. Forget the report designer. Make one report: last week's sales by site, the one area managers ask for every Monday, fixed, with no options. It opens, it prints, it exports. It is embarrassingly small, and it is whole. Someone can start, finish, and walk away with what they came for.
A whole thing also teaches you something. People use it, and what they ask for next tells you what the second report should be. Half a thing teaches nothing, because nobody can get to the end of it.
The hard part is giving up the big plan where others can see. One fixed report looks like a failure of ambition beside a "reporting suite" on a roadmap. But the suite, cut by layers, would have shipped as nothing at all.
The same holds inside the work. Get one path working from the first click to the saved result before widening anything. Then at every moment there is something a person could use.
Therefore:
When you cannot build all of it, do not build part of everything. Build the smallest version a person can start, finish and get real use from, and widen it only after people have used it.
In practice. Ask of whatever is in progress: if we stopped today, what could a customer do from start to finish? If the answer is nothing, cut it again, differently.
Goes with. How small it must be follows from DECIDE WHAT IT'S WORTH (21). For a newcomer, the smallest whole thing is a FIRST USEFUL RESULT IN MINUTES (34). What to widen next, you learn when you CHECK AFTER YOU SHIP (28).