The project management workflow of the Rational Unified Process is useful for balancing competing objectives, managing risk, and overcoming constraints to deliver a product that meets the needs of the customers (the ones who pay the bills) and the end users.
In an iterative process, the development should be based on a phase plan and a series of iteration plans.
Risk is a driver for planning.
Measurement is a key technique used to control projects.
In building a phase plan, you must assess trade-offs between staff, schedule, and project scope.
The criteria to define the scope of an iteration vary from phase to phase.