Agile Checklist Part 2
Decide on which aspects of agile you will apply to the project.
Note that the impact will vary very much depending on this.
Aspects like pair programming or test driven design can be applied locally, whereas continuous integration, for example, has a broad impact on the project, and may require the participation and cooperation of all contributing toward the project.

As a general rule it is difficult if not impossible to use a mixed agile & waterfall approach.