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 all right 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.
Feel comfortable taking suggestions from the casting director or Executive Producer. Don't feel insulted if they offer suggestions. They are trying to get the best performance out of you. If they think you are wrong for the part, they wouldn't suggest anything, they would just wait for you to finish and move on to the next person.
If you are serious about TV acting, you will go on many auditions a year. And audition for many of the same casting directors over and over. The TV community is very small in the casting department, especially for the major network shows. So be professional and build relationships. If a casting director keeps seeing you and sees improvement and drive, they'll cast you if the part is right.