Was waiting to see when you were gonna finally post! Good job 
Based on the car sketch, the first thing you should definitely study is perspective. Practice drawing cubes and rectangular prisms of various sizes and in various views. Let’s get your perspective down first.
Some key words to look up in your books or online “how to set up perspective guides” / “1,2,3 point perspective” / “cone of vision” / " horizon line, eye level" etc… it looks like you already have a couple books… Im sure you can find and lear the basics in the first chapter or two. Foundation is KEY! Get that down and it’ll be smoother sailing for you.