This comes up way too often I'm sad to report. I have heard from people in the industry year after year that there are simply too many people who have great VO demos who don't read with the same competence in the booth that their demo displays. It is incredibly important to practice all the time as if you're in a booth doing a job. Go to a gig all warmed up and sharp. They aren't there to listen to you wake up or get rolling. If they greet you and chit chat fine, but don't start telling long stories. Be prepared. Be on time. The first read out of your mouth should demonstrate that you are a pro and ready to go. Time is money, and it's their money.
In order to really be able to take direction and deliver professional reads, you have to be able to vary cadence and melody to solve problems of articulation and or meaning. Have fun out there and practice like you're going to the olympics. You can do it, you can succeed.
