To be most agile with your communication, understand several models of learning styles, where you fit into them, and where your team fits into them. By tweaking the ways you communicate to fit the information and the situation, you are helping your team remain agile by valuing people and interactions over processes.

Research suggests that humans are biased, not-very-rational decision-makers. We believe we see things clearly when the evidence shows otherwise. Throw in a big dose of optimism, and it's easy to see how estimating software projects can be problematic. Our best hope is to construct diverse groups with varied viewpoints.

Scope, schedule, and resources: Whether you’re using agile or more traditional project management approaches, this triple constraint is the law of the project universe. The unmentionable “third rail” of project management trade-offs is compromising quality to deal with the other two aspects. Don't make that an option.