I worked as a researcher in TV as a new graduate, and we would advise people to avoid close stripes - either way - and small prints like gingham/dogtooth checks, because they can strobe on transmission. (Mainly just really distracting and annoying for viewers.) If you're part of an audience/group a bold, plain colour works best, or a print which is fairly distinctive, so leopard print instead of floral (which can look muddy unless it's very bold), for example.
I know you didn't ask about makeup, but the camera can really wash you out. Off air people like newscasters and hosts tend to look quite dramatic, whereas on screen they look "normal".