Agile methods promote a disciplined project management process that encourages frequent
inspection and adaptation, a leadership philosophy encourages teamwork,
self-organization and accountability goals.

Agile Development Methodology
Scrum
Methodology

Agile
Model

Iterative approach is taken and working software build is delivered after each iteration. Each build is incremental in terms of features; the final build holds all the features required by the customer.

Agile Manifesto
Principles

Individuals and interactions −In Agile development, self-organization and motivation are important, as are interactions like co-location and pair programming.
Working software −Demo working software is considered the best means of communication with the customers to understand their requirements, instead of just depending on documentation.
Customer collaboration −As the requirements cannot be gathered completely in the beginning of the project due to various factors, continuous customer interaction is very important to get proper product requirements.
Responding to change − Agile Development is focused on quick responses to change and continuous development.