Create a New Project
You need to get reference photos:
Top/Bottom, Side, Front/Back
How to Create an Image Plane for a camera:
In outliner, click on top camera
Then pull up the multilister by Window > Attribute Editor
OR button in menu
click on top shape
In attribute Editor scroll down to Environment tab
click Create near image plane
new window opens set the parameters as follows:
Image Plane Attributes
Display: looking through camera(if you want to see the image only in the top camera view, otherwise select in all views)
Display Mode: RGB
Image Plane: Fixed (this way when you move the camera, the Image Plane and the refence curves you draw will follow it)
Type: Image File
Image Name: here you have to load the file you will use as reference
Scroll down & also set up the Placement Extras (Note you need to consider the size and proportions of your image when making a decision about the width and height)
Center: 0 0 0
Width: (Make this proportional to your image)
Create > Curve Tool  (make it 3 Cubic)
( Tip When you draw a curve you have to use less CV as possible; this way you will control the curve easier and your model will be "lighter" too. In this case you don't need to pay great attention to this because the curves you draw will only be a reference). Once you have drawn the top and bottom profiles rename them bottomProfile and topProfile
(Tip When you rename something in Maya, it's better not to use spaces or underscore. Try to use compound words with capital letters; this will work better especially when you will use expressions).
Now, since you don't need to modify them any more and since they are only reference curves, you can template them.
Before doing this it's better to assign these and the other profile curves we will create to a level. The use of the layers is extremely important; using the Layer Editor you can hide, template or select the different parts of your model very easily. So to assign the curves to a new layer:
Window>Layer Editor 1.
Click the New Layer button 2.
Click the Rename button and rename the layer referenceProfiles 3.
Select the bottomProfile and the topProfile 4.
Click on the Assign to Current button.