There must be some local or online interview skills training that would be helpful for you.
I interview a lot. Usually by phone, sometimes video call, occasionally in person. There's definitely a skill involved. But I think being well groomed, confident and friendly is a good start. They're looking for a new member to add to the team. Not the time to display humor. Just professional, to-the-point answers. Have your "strengths and weaknesses" answer figured out well in advance. Pick a strength and present it as a weaknesses: I'm fairly meticulous about spotting typos. Sometimes correspondence with typos can be somewhat distracting for me. I have to remember to focus on content and take off my proof reader hat.
I just saw how old this thread is. Hopefully the OP is alright and hard at work at a new job!