First and foremost, it is still a "genuine" interview, and should be addressed as such. There is a person on the other hand who will be making an executive judgment regarding the credentials for the position, so presume it's no different than if you knew this individual in person.
Dress to impress! Even if they won't see your feet, dressed from head to foot in at least business casual wear is the first way to not only appear professional as the camera goes live, but help you move into the correct mindset. You'll be shocked how you can believe you should take on the planet when you LOOK like you can!
Find a calm and professional place for the interview. If you have a home office, this is excellent. If not, most libraries have meeting rooms free of charge, which you may book for yourself for the length of the interview. There is nothing less professional than children, dogs, or other domestic distractions invading on your interview experience, and substantially damaging your look of professionalism. If you cannot get away from the house, set up at a dining room table or in a living space, just make sure everybody in the home understands you need some protection for the allocated period of time.
Try out the interview system in question before the interview. The day or night before, log in and familiarize yourself whether it's a software you've never used. And if it is something you use regularly, including FaceTime, double check that you have the contact details right.
Pay particular attention to the time zone the interviews are conducted in. This one is SO critical. With the development of virtual interviews, organizations have opened themselves up to a vast network of persons all over the globe, which although useful, also likely implies they function on a different time zone than yourself. No one needs to start started with a poor foot because you skipped your appointment or were late because you were unaware of the time zone. If it isn't clarified somewhere in a clarification of any sort, reach out to your recruiter or interviewer, they would be pleased to send you the specifics, and grateful that you were diligent.
Try to utilize a laptop or desktop if at all feasible, but if you have to use a Smartphone, set up a tripod setup beforehand, so your hands can be free for the interview. You may also use a stack of books. What you don't want to do is keep the handset for the remainder of the interview; this is a formal experience, not a FaceTime session with your grandmother.
Like any interview, make sure you have researched up on the organization and job you intend to occupy. Google them. See whether they have had any news recently. Did they recently integrate with anyone? Or maybe they made a naming transition not long afterwards. At the very least, recognize the products and/or services they provide, and be prepared to inform them how you could help them in this niche if you were recruited.
Prepare questions. Almost often the interviewer will ask you if you have any questions, and if they have answered all of them, is OK to tell them so. However, this is your moment to have their entire attention, and ESPECIALLY if you are given a position immediately afterward. You would like to have prepared a summary of everything you may have liked to hear, rather than bombarding the interviewer's mailbox with emails fewer than 24 hours after they had time set aside to make themselves accessible only for you.
With these recommendations you will be well on your way to not just acing your interview, but employment offers aplenty! Break a leg and most of all, be yourself, and let your personality show!