The agile software development approach consists of working through a development project as a series of short, focused cycles. Often called “iterations” or “sprints”. After each iteration, the team evaluates the results and adjusts the plan as needed.
The high level concept of Agile is:
Deliver value first: Features are built in the order of business value, ensuring the most valuable work is completed first.
Maintaining high quality: Quality is a top priority throughout the development process, not just at the end.
Meet a delivery date by adjusting the scope: Instead of extending deadlines, or reducing the quality, the team adjusts the scope of what gets delivered to stay on schedule.