TV auditions are very similar to Film and Theatre auditions. The main difference is time. Television is always under a time constraint. A script is written in a week, and that next week it must be cast, in order to film the week after that. A large part of television is guest cast and speaking extras, since there are a limited amount of recurring roles on television shows, episodic character casting is what most TV auditions are for.
Casting directors understand that sometimes when auditioning a TV role, the actors may have had only a couple of days to review the lines. Some don't. This is why, no matter how much time you have to rehearse before an audition, KNOW YOUR CONTENT.
It is alright to read straight from the pages during your audition, but if you have memorized your lines, try to look up and show your face to the casting director. Sometimes you will be reading a scene with a casting assistant. Most of the time, these assistants are not actors and may have no energy. Just do your best and worry about your delivery, not theirs.
When entering the room, slate (introduce) yourself and the part you will be auditioning for. If the casting assistant did not take your head shot in the hall, someone will take it in the audition room. Be brief in your introduction and wait for the casting director to be ready. In most TV auditions, the people you will be auditioning for will be the casting director, an assistant, usually the executive producer of the show, or the writer of that specific episode, and maybe a camera person if they are rolling tape. TV auditions always run tape so casting directors can review auditions afterwards or show an actor to the EP if he/she was not in the room. An EP puts a lot of trust in the casting director because the EP will not always be able to attend every audition due to their other writing and producing responsibilities.
After your performance, thank everyone in the room and exit quickly. Wait outside for a couple of minutes incase the casting director wants to see you again. Then sign out and leave quietly and professionally. If you had a bad audition, do not let it show to the other candidates. Always look confident entering, leaving and during an audition.
The big difference with TV auditions is not only the time to cast, but also the time for an actor to prepare for a role. A casting director may see your headshot and ask you to come in the day of the audition. If this happens, stay calm and know that the casting director is aware that you have just received the content that day. Just read the lines and do your best. You've obviously been called in because they like you so prove that you can adapt to any situation and blow them away in the audition.