As an experienced therapist with high standards we expect you'll make a client feel comfortable and heard, and that you will be honest with them about what they can expect from therapy and if you have the right skill set to help them.
Otherwise, we'd ask that you discuss with the client their motivation to continue sessions, ideally looking for a minimum commitment of three to four sessions. This allows you to complete an extended assessment.
We'd also ask that you carefully go over cancellation rules and terms and conditions (T&C's). Even if such paperwork is sent in advance, in our experience clients absorb more when it is shared again in the first session.