Xian your work's nice and the lighting is not bad at all since it clearly shows the detail on your model but if you are going to primarily show your models then its good to have better staging and composing skills with the camera.
These skills can only be improved by observation.My composition skills were terrible until i started watching movies.Not hollywood in particular but movies that carry themselves on great cinematography and lighting. Also referring to books that deal with the above will help tremendously, mind you im talking about a permanent solution to improving skills related to lighting and composition.
One good excercise is to see a particular shot that you like in a film then roughly sketch out the shot on paper trying to replicate the exact composition in that frame.Like a storyboard frame.
There are lots of books out there regarding cinematography and lighting.If you do not want to invest in books then the internet is always open.Im sure there are tutorials out there on camera staging and lighting.I will try to look up some links that will be of help.Meanwhile some of the books are:
The Five C's of Cinematography: Motion Picture Filming Techniques
by Joseph V. Mascelli
Setting Up Your Shots: Great Camera Moves Every Filmmaker Should Know
by Jeremy Vineyard, Jose Cruz
Shot by Shot: Visualizing from Concept to Screen
by Steven D. Katz
Digital Lighting and rendering : Jeremy Birn
Some of the must see movies that may seem boring, but are phenomenal examples of the above and are a valuable source of study are:
Nostalghia : Andrei Tarkovsky
Three colours :red,green,blue : Krzysztof Kieslowski
Citizen Kane : Orson Welles
Amelie: Jean-Pierre Jeunet
City of Lost Children :Jean-Pierre Jeunet
Blade Runner : Ridley Scott
Well there you go...dont know if i have been of help here but hope that helps more in the long term.