An add-on to the previous item: If you are making a demo these days to try to get an agent, do not make it two minutes. Make it one minute and assume that if the listener does not hear something in the first thirty seconds that grabs their interest, they will never make it into the second thirty seconds.
If it does snag an agent and cause them to sign you as a client, your new agent will probably want you to make a new demo which they will use to try and get work for you. They will tell you how long to make that demo and what to put in it in what order.
And before someone asks me what to put in that first thirty seconds that will grab an agent, here's the answer: Something they haven't heard before that some client might want. Sounding like everyone else is the last thing you want to do. I recently listened to the demo of a young kid seeking representation. He started his demo with a killer imitation of Bart Simpson. Not only will that not get him an agent but few agents will make it past Bart to hear if he has anything else to offer.