Whether you're a new PPL, or very experienced, the care you take of your passengers should be the same. Being an experienced pilot will add a layer of safety, but if you're keeping the flight safe anyway, that should be fine, you passenger won't know the difference. Do not fly to the limit of your skill, fly to the comfort and enjoyment of your passenger. I have observed that newer pilots are sometimes less casual about the flight, and in being so, demonstrate more care for their passenger. When flying a plane is routine, a pilot's interest in the passenger's ride may be too.
As said, keep the flight short, until you're confident that passenger is at ease being airborne. Choose a smooth day. If the passenger seems uneasy, or stops speaking, they're probably feeling airsick, and may not want to say - head home. If you know that your passenger is not feeling 100%, bank as little as possible, and draw their attention to features on the horizon, not below the plane.
Assure that they receive a briefing about seatbelts, exits, fire extinguisher, and first aid kit, sufficient that they can help themselves (and you) if you cannot. To the extreme, when I used to take my daughter fly in camping, I prepared detailed instructions on bright pink paper, and put them in a zip lock bag in her side pocket. I told her they were there, and if something happened to me to read them.
Telling your passenger to keep their feet off the pedals is impractical in some types, particularly if they're tall. I prefer to tell them that I don't mind if they rest their feet on the pedals, they will feel them moving - just don't oppose the motion they feel. I've never had a problem - and less worried passenger.
Taking a passenger is not the time to show off, it's the time to impress them with a boring, smooth flight - zero of "watch this....."