Make the new cuts shown in green and adjust vertices as necessary. You will notice that in making these cuts you create two triangles shown by the red numbers. This is easily fixed my target welding vertex "A" to vertex "B." This will result in another triangle being formed but that one is OK for now so just leave it as it is. We will get rid of it later.
More detail is needed in the front. Instead of using the cut too that we have been using so far, there is another tool that will work better in this case. Next to the "Cut" button there is a button labeled "QuickSlice." This button works like a cut but cuts in a straight line across all polys that it crosses. Click the button and then click at one end of the green line then click at the other end to do a quickslice.
Do another quickslice as shown by the green line. This slice is going to help us shape the light. Adjust vertices as needed to get a nice smooth shape.
Now adjust the vertices shown in red so that you start to shape out the headlight. Don't worry if it doesn't match up perfectly with the blueprints. We will be tweaking it later.
Now we are going to start moving faster because most of the stuff we do from here on out is just repitition of what we have already been doing. Starting with the edges shown in green, shift-drag them twice and then adjust vertices to get the shape shown in the pictures Also adjust vertices to form the shape of the headlight as shown by the yellow octagon. When smoothed, the headlight should be perfectly circular so all the sides of the octagon should be the same. A little trick for doing that is to draw an n-gon with 8 sides in the front viewport approximately the size of the headlight and then adjust the vertices to line up with each corner of the n-gon. When smoothed, there should be a perfect circle for the headlight.