This may sound obvious. But it is key, and you will definitely feel it if you don't do it.
So, in case you don't know, to give some ideas of what this may involve:
- working days/times
- availability/ability/time to respond (if you are out at court a lot then explain this in advance)
- how best to get a message to you (email, secretary, etc)
- the likely time before there will be something new to discuss
- the likely time-scale for the whole thing
- the cost, and how and when payments will need to be made (be confident with this, it is an exchange, they are expecting the advice/your expertise to cost them money)
- your full attention for their time (ie. in a meeting, ensure your phone and notifications are on silent)
- if you are running late (it happens) let them know asap (as you would want them to do for you in future)
- mutual respect (remember this is a relationship, working on something together that they couldn't do without you but you also couldn't do without them)
Consider if you were waiting for test results. What would you want to know? When they are likely to be in, and how they will be communicated to you, or whether you need to book an appointment. Also possibly when they are open and you will be able to get through to the right person, and what days can the appointment be booked. Without these basics people can panic in the 'not-knowing'. Not knowing what to do, when to do it, how to do it, whether they should, etc. It can easily cause a spiral of over-thinking, anxiety, and predicting the worst.
In the professional context this can lead to agitated, annoying, or frustrated clients. And to be fair to them, it is our job, as the professional, to explain, build, and maintain these, to put them at ease. So they know what's happening in their life and feel some semblance of control. However also know that when you say 'the minute I hear anything I will let you know', you have to do it, or else their trust in you will take a hit (and so will your reputation).
And yes all this information may be in the first letter or in the first meeting. But may I remind you how much other important information is given at the same time? So be kind. This is our work, but their life.
And honestly nothing will build your client base faster than happy client recommendations.