Begin with the operating model
Before sketching screens, identify the objects the business cares about, the states they pass through and who is responsible at each point. A quotation becoming an order is not just a button click; it changes commitments and creates new work.
Design hand-offs explicitly
Many failures happen between roles. Sales expects finance to see a change. The workshop assumes the counter has confirmed stock. Good systems make ownership and status legible instead of relying on memory.
Treat exceptions as first-class work
Operators need safe ways to correct, reverse and explain. An audit trail, permissions and helpful validation are not administrative extras; they are part of making a system trustworthy.
Optimise for the life of the system
A successful launch is the beginning. Data quality, support, performance and the cost of changing rules will shape the product for years. Technical decisions should protect that future without over-engineering the present.