Car Photo: Turn the wheels to face the camera and make sure they are exposed correctly, may take a few shots layered to get them "right", don't get distracting objects in the frame (Cars, signs, doors with words, flared lights, etc...)
The city picture is cool, may be a little better with a different tone, not so orange, but i light it!
the others are more snapshot like, but glad you like the camera, read read read and practice practice practice!
I like the 3rd one. Wish it was a little lighter though, I'm new to photography, so its the ISO I believe should of been Higher? But then again - the lights would probably over do it.