Hi
Your hand drawing sketch is really good i suggest you to try more but i think you have spent much time to draw yours.Try to draw more qiuck sketches like professional designers.
In Autocar magazine there are usually some quick sketches.These sketches are quick but they are precise.

Bye

Very nice...

but I think the right part of the back should to be a little bit higher or parallel to the horizon.

the farside rear arch looks a bit too high, and id recomend using bigger paper too so u can draw the whole car! needs more contrast in shading and highlights as well. beefing up the lineweight in places would help too.