Of all the things that make your film look more like, well film, lighting is the most crucial. Yes, 24p will help, and a good dynamic range can go a long way, but lighting will sell the look of your project. It doesn't matter if you are a monster budget producer shooting 35mm film stock or an independent film student working without any money you need to consider lighting.
If you don't know too much about it; just learn the basics of three-point lighting which is the most common style used. It consists of a Key Light, a Fill Light (lit or bounced) and a back light (rim light.) Using two or three of these lights can give your on-screen talent the look and depth they need to really stand out.
The Key Light is usually positioned at about 15-45 degrees off the camera toward the subject. The light is the primary source in the scene and usually represents a light that would be found as though it were a practical.
The Fill Light removes the harsh shadow that may form on one side of your subject (opposite of the key light). The Key Light and the Fill Light are different intensities and thusly maintain some degree of shadow. A Fill Light actually doesn't even have to be a light at all; it can simply be a large piece of foam board (white) used to reflect light back onto the subject from the Key Light.
The Rim Light is crucial to finishing off the look you are going for. This light should be fairly high and behind the talent and will create a soft glow on the edge of the subjects shoulders and hair. This is why it is often referred to as a hair light. This brings the subject up and separates it from the background giving the shot a sense of depth on the two dimensional film.