This is a step-by-steptutorial that explanehow to create 350Z's body using polygonal modeling in Maya environment, but you can apply this technique to other poly-modeling software.
This is my screen-shot after I have correctly placed my blueprints.
To start with, we'll concentrate on the front part of the car. I've divided it into 3 parts just like it is in real life too, each part is defined by cuts as shown in the picture. Start with the modelling of part 1.
Create a polygonal cube and using the Scale and Move tools try to give an approximate size of the part of the car that we want to model. You should have something like this.
For a better control over each point of the surface, we must subdivide our cube in more sections. To do that, select the cube and go to the Channel Box (, on high on the right). Roll down until you see the PolyCube1 point, this is the name of the cube that we have just create. Do double click on the name, to open the Property of the object and set the Subdivision With to 6 and the Subdivided Depth to 2. Now, do one click on the write PolyCube1 and change the name if you want. Move to the Side View and eliminate the faces behind and below. Make the same for the faces of the superior half in the Top View.
Now, selecting and moving the vertexes, try to give it a more defined form as possible, following the blueprints in all the three view. The result should be like in the screen-shot.
Besides I've eliminated the lateral faces that don't serve me.
For define our model, we have need of other polygons (subdivisions). To do this activate the Split Polygon Tool command and in the Top View, traced some lines (the lines must start from one edge and finish on another one, and at the end you must confirm that with the Enter button on your keyboard) in the parts that request a major control, and adapt the new vertex to the blueprints. Try to not abuse of the Split Polygon Tool command, this is important, try to create only polygons that serve you. More useless faces, become only a problem because the surface become then uncontrolled.
To make a cut on the hood begin to define the form using the Split Polygon Tool. Unfortunately the cut that we want to do, don't coincide with the end of the piece that we modeling in none of the two extremities, that will tends to create some difficult and problems. Remember that the polygonal models in Maya must have 4 edge (namely 4 vertex), so try to avoid polygons that have 3, 5 or more edge because them tends to create problems with the smooth comand.
In the last screen-shot you can notice that we have create 3 irregular polygons that must be adjust: from 3, 5 to 6 edge/vertex. Using Split Polygon Tool try to build 2 lines like in the picture.