Show some human lighter side material (comedy and/or just being you). It is important they see you can create a character built on who you are, one that is believable and makes the audience want to know you, watch you and learn more about you.
Pick clips that showcase your face and your strengths not the actor you are working with or what you think they want to see. What are your best performances and what communicates that without looking as if you are anyone but the character, real person, you portray?
Keep in mind that the trend now is thirty second demos..put together and expanded a bit for agents and showcase. Actors Access provides a service to cut your demo into sections and label them. Casting Directors, as their workload increases and the old timers who use to care about and go and see talent in plays, watch entire movies or sit through longer tapes pass the casting torch to younger multi-tasking professionals. CD's will tell you they only have seconds or at most a minute to make a judgement about your performance on a demo.
Casting wants only the clip or clips that fit what you are auditioning for. Make sure you are the focus,...other actors do take over some of your demo by their own strength.
The tape for agents or managers should be closer to the traditional demo, as you are selling them to become your partner and employee, to believe in you and in effect sell you. While Casting Directors may have your photo and demo as their first and primary contact impresion, a tape for an agent usually comes after you have already communicated with them and both you and the agent have shown an interest in being represented.
There are several producers who do demo reels in Las Vegas, however the best clips remain clips from actual films, with a focus on union main streem films.
Be sure you can be seen (not too dark, not out of focus, not in large group)and your character has something that can be seen as a dramatic arch moment (meaningful emotionally or in character development).
..Call me if you like.