Good advice from mafloral, just wanted to add something extra. You need to pay close attention to horizontal and vertical alignment and padding.http://pbrd.co/Vajga6
I’ve highlighted the bits in red as a problem with horizontal alignment. Also it is good practice to make sure your vertical alignment is roughly equal as well. If you’re not using a grid system I would advice so.
And on your menu in responsive mode be sure to further indent sublevels.
Main menu -Sub menu
This can be easily coded.
And by the looks of it, for your 3D renders you seem to be using cycles, I apologise if I’m wrong but I’m just taking a guess here. That being said you can achieve a nicer render with a good light setup. It looks to me you’re using global illumination or just one large emitter. With the right setup you can dramatically change the quality of your renders.http://www.youtube.com/watch?v=yvB_pm3YMDA
That would give a better overall look. Good luck.