I have a tutorial on camera lens focal length effects (among others). The default lens focal length causes lots of geometric distortion (it's not technically distorted really, but that's a long story). This is because it's a wide angle lens meant for landscapes. Read my tutorial, or just use a focal length of greater than 60mm or 70mm and move the camera back. 

Your scene lighting needs to be much more dramatic (i.e. much less flat and less front lit).

Notice that moving the sun's location around the scene has no effect (after all, it's 93 million miles from the camera). It is rotating the sun that changes the lighting. Also, I always turn off "points at camera" for the sun, to give me more control. And the sun shadows are typically too dark for mid and closeup work. Try 70% to 80% shadow intensity. 

A typical newbie problem is ignoring material scale. Getting the scale of materials right makes a big difference to realism.

Until you understand materials (and eventually get into the function editor) you should prolly use the standard materials or download those of more experienced mat creators.

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