Develop quickly, deliver often.
Share what function you want the work to perform. When the work barely performs that function, resist the urge to enhance, stop working on it and ask the group what direction to take next. This allows for agile changes in direction.
Work in small groups where you can hear each other from where you work.
Commit to making yourself available face-to-face to customers or appoint someone who can make face-to-face commitments to customers in your name. This principle separates the cowards from the brave.
Do little bits of work and make sure they're useful before you do more work.
Have milestones every few weeks in the calendar where you make sure what you've made is stable enough to release.
Tell everyone in your small group what you did yesterday, what you plan to do today and threats to doing it.
Don't measure your progress by what might work tomorrow. Measure your progress by what works today.