Of course it is important to be a good actor in order to get a job on television. Acting class, auditioning class, performing in plays, doing student films, watching films and television, reading instructional books and periodicals all help round out an actors understanding of what will be required of him or her.
But there are a few additional things to keep in mind when preparing to audition for television. Be a professional. Be on time or early. Allow time for parking or traffic delays. Dress for the part. (Don’t go in costume, but suggest the character in an appropriate manner.) Be friendly and polite, and remember to thank the casting assistant, and the casting panel as you leave the room. Understand that you are one in many actors the casting directors will see for each part. It makes their jobs easier and gets you called back again and again if you give them confidence that you will get the job done in a professional and artistic manner without attitude, excuses, or baggage.
Learn your audition material well. Allow for nervousness to diminish your prepared homework by about fifty percent. Don’t wing it! You must allow enough time to learn your scene or casting will stop calling you in. Don’t waste their time, and take full advantage of your five minutes in the room. It’s all yours, you own it. Take control of the impression you make.