Some software allow tyou to look at multiple viewing directions simultaneously, like an iso view, a rh side a rear and a plan.
Bryan is correct though- learn to focus on the trihedron so you don't get lost as to X, Y and Z directions. Try to biuld your models where -X is fore, -X is aft, +Y is away from you, -Y is toward you, +Z is up, and -Z is down.
I try to start all of my models where the Z=0 is top of rail, X=0 is centered in the length of the object, and Y=0 is centered in the widht.
This way if the car is symmetrical about the Y-Z plane and symmetrical about the X-Z plane you only need to design one quarter of the car, and reflections can be used to finish the rest.
Learn about boolean operations if yourCAD tool supports them.