Vray external rendering

Suzidar87

Hi, I am trying to complete an external street view render. I have a few questions:

How can I increase the speed of the render without effecting the quality?
What are the best render settings for external renders?
How can I get a sky in the background?
Why are my shadows not showing?

I have turned on shadows with the skecthup settings. I have also removed the items which are not viable in the scene to see if this will increase the render speed.

Thank you in advance.