The answer to this question depends on the culture you are interviewing for, as you should dress as if you were attending an actual interview. How do you know the general dress sense of a company? The best tip is to visit their Facebook, Twitter and Instagram pages to gauge the level of formality in a particular organisation.
Beware of falling into the trap of dressing formally from the waist up and wearing shorts and flip flops below the waist as they won’t be visible underneath the table! You may have occasion to get a glass of water or fetch some documents during your interview and your khaki shorts could be a source of great mirth if they suddenly become visible on camera.
In addition to deciding what to wear, you should play close attention to your surroundings of where you are going to have your Skype interview. If your kitchen is in a complete mess, why have an interview in a room that is surrounded by general chaos? Keep cats and dogs out of the room as pets sometimes tend to jump up on your lap, which could prove very distracting during an interview.
Try to inform the other people in your house that a certain room is out of bounds as you are being interviewed over Skype. It will be extremely distracting for your interviewer if someone is cooking in the background, clattering pots and pans and making a general nuisance of themselves.
In essence, dress as if you were attending an actual interview and ensure your surroundings are neat and tidy, as you don’t get a second chance in making a good first impression.