29. The highlighted faces (Fig35) were created with an extrusion and the verts near the door surface have been snapped to it (keep these surfaces separate). Remember to shape the new verts as you go, paying attention to the shape of the front fender.
30. Two more extrusions should see you end up with something similar to Fig36. Keep shaping as you go along and snap to the door verts to keep a nice flow to the model.
31. If you look at references of the front fender, you will notice a crease in the surface. This is where we have extruded out to so far. I like to then extrude outwards and snap to the curve representing the end of the fender (Fig37), before cutting detail back in and shaping (Fig38). Remember to leave a gap for the headlight.
32. The final thing to do is to extrude the edges surrounding the headlight to get the highlighted faces in Fig39. Shape these new edges to follow the flow of the front fender.
33. The rear fender is probably the hardest part we have tackled so far, mainly because it needs to flow in many directions at once. Good references are the key here. Notice how the fender curves smoothly above the door before bulging out for the wheel arch (Fig40). This is quite a tough piece of geometry to get looking right!
34. Start off by outlining just above the actual wheel arch and the top most curve of the side air intake (Fig41). The two highlighted curves emphasise the previous point about the fender's curvature.
35. Extrude the front part of the fender upwards, following the curvature of the car (Fig42).
36. Next, extrude the back edges of the fender and shape, as shown in Fig43. Try to model the bulge of the wheel arch while keeping a clean distribution of polys.