Well, it looks like your starting to step away from the basics.
Now I think you should start working on being able to make thin lines and being able to control where they go more.
Some of your lines don't follow each other, most easily noticed in your front tire that looks you tried to run over a curb...
The better you get at these two aspects, the smaller the details you'll be able to add. You could eventually be able to draw each individual fin on the radiators!!! Well, theoretically....
Oh, and seeing as how you bought a whole pencil se (which can be kinds expensive), you never thought about an erase shield, did you?
These will REALLY help to get some of the finer areas....
Just be careful, they're an extremely thin piece of metal.....it gets bent, you might as well get a new one....
Well, GOOD LUCK!!!
And try putting a bit more time into it....just like getting laid, you don't want a "quicky"!!!!
Sorry, I had to say it!!
Well, quit reading this and GET TO WORK!!!!!!
Oh, and good luck