Drawing out instead of explaining
Avoid top-down discussion of how the client is "at the center of our concerns"! It will be too general to engage the team members. The "client" mindset is first and foremost a set of attitudes and practices which must be meaningful for the team: In what ways is (internal and external) client satisfaction a priority for us?
Work togther to define objective indicators
Nothing is more vague than the notion of a client-oriented mindset!
An essential step: together with the team, define concrete indicators which are easy to observe, and which will show us that we are making progress in our client relations.
You construct thereby a commence reference for how you work. It may be a question of response times, habits of communication, types of responses...
Engage the team in tracking progress
Transforming the objective into concrete actions implies that everyone be invested in the monitoring aspect: Where do we stand now? What is working? What is holding us back...?
Several ways to share this information: etablishing regularly-scheduled steering meetings, choosing a tool for supervision and collaboration...