Leave useful architecture behind.

Architecture in this sense means the shape of the thing, the decisions that determine what is easy and what is hard for everyone who comes after. Most of what you make will be replaced. The structural choices tend to outlive the content, and people work inside them for years without knowing who made them.

Give disproportionate care to the decisions that will be expensive to reverse. The naming, the boundaries, the defaults. Details can be fixed later. Structure hardens.