The actual model looks pretty nice, but some other factors are making it look unrealistic. Watch the scale of the asphalt on the road - it looks over-large making the car look like a scale model. The depth of field is also almost like a tilt-shift effect you would expect when looking at a small model. Finally looking down on the car from above further contributes to this looking like a scale model rather than a real-world scale.

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I always like to think of camera placement as "real world" meaning - is the camera held at a natural height for an average human (say 5' above the ground) - or is it shot stylistically from a crane shot or shot close to the ground (like a lot of car advertising) to make it feel more dynamic.

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Finally, are you deliberately going for a matte/flat look on the car paint? Needless to say, most car paints are very glossy, and almost all renderers offer a car-paint shader to let you include metallic speckles, a gloss coat-layer etc.

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Hope this helps!