One of the most important things that you can do with your clients is develop trust and integrity. The simplest way to achieve this is to say what you are going to do; and then go out and do it.
Build visibility into your process and acknowledge when things are not going according to plan. Visibility implies that people know what you are doing and your current status. Traceability supports this function by allowing people to quickly navigate through your work.
If you can set expectations and deliver upon them; then you will be well on your way towards developing trust and integrity with your clients.