A client I coach was talking to me about his auditions. We talked through the auditions he was getting for the week - most of them being commercials, and one of them being a tv role. I asked who he was going in for - and I also asked about the show he got called in for. The most surprising thing I came across was that he wasn't able to tell me what offices his commercial auditions were for, and he knew nothing about the tv show.
One of the things I can't stress enough about working for yourself is that you're running your own business. A huge part of your business is knowing what business you're doing - if you are getting commercial auditions - you need to know what offices you are going to. You should know the difference between House, Melsky, Telsey and Liz Lewis. You should know the names of the casting directors you're going in for and you should be mindful of what products/roles you're getting seen for. When it comes to tv roles - it's important to know about the show. If it's a pilot, then at least you can do research on who the writers are, who's producing it, what roles are already cast, if any. And if it's an existing show - you should watch a couple episodes to get a feel for the style of the show.