I'm retired, so when I schedule a play date, I always like noon to 2pm, if I can do that and my partner can accommodate.
I eat enough a few hours before hand to sustain me, but I don't want to be full/bloated. I eat some fruit if I have it. I hydrate well, but try to empty my bladder before I arrive.
Depending on my wishes, I will enema within 2 hours and I try to schedule my shower to be within 1 hour of departing, so I can allow an air dry before dressing.
I floss several times a day before the date, use mouth wash several times a day after each floss to kill as much bacteria as possible, brush several times a day, because, duh. I have a travel bottle of mouthwash and use it right before I head into the session.
I have my consideration counted, several times, and stashed in an envelope... with more Benjamin's in my clip because, you know. Depending on if it's a regular or a new date, I may include something extra in the envelope, or, have a gift bag of chocolates or sometimes pet treats if I know they have a pet.
When I walk in the door I'm clean, dressed nicely but comfortable, don't stink, and show them respect and that I'm happy they've allowed me into their space.