Communicating with Clients

Reporting on Work

Use Trello for quick updates, mention all relevant parties so they get a notification.
Email may be appropriate as well for more substantial updates that deal with several Trello cards.
Show the clients you work for something at least once a week. You can use Screencastify chrome extension for it (More details).
Keep it visual. Use screenshots, mockups, videos, and links to staged apps as the primary way to demonstrate work to clients.
Try to anticipate what problems they will have when using the app, and test the ways you expect them to use it in order to make a seamless experience.
When reporting on work to clients, re-state what your commitments were and how much is done.
Indicate anything that's currently overdue or other unmet commitsments as early as possible, indicate how you're fixing it.

If something's unclear to you, as very specific (not open ended) questions and state your assumptions so far so they can point out any miscommuniation.
Be concise. Most clients get a lot of email so stick to key points that will matter to them. Be respectful of their time, and avoid asking for something if you've not made an effort to solve it yourself.
Show appreciation for the client's time, and anything they've done to help the project along.
Send the communication to only the people who will find it relevant, and copy all team members who have been involved in the project.