Try this "Line - white - Line - white - Line" combinations in PS :
(1)
6 inch (color) : 2 inch (white) :
2 inch (color) : 0.66 inch (white) :
1 inch (color) --- this is in 1 : 1/3 : 1/6 ratio.
(2)
6 inch (color) : 2 inch (white) :
2 inch (color) : 0.66 inch (white) :
1 inch (color) : 0.33 inch (white) :
1 inch (color) : 0.66 inch (white) :
2 inch (color) : 2 inch (white) :
6 inch (color))
- Lines should start at the top of bonnet and run all the way to the bottom of bumper.
- Try "1 : 1/3 : 1/6" ALONE from driver side
- Try "1/6 : 1/3 : 1" ALONE going towards passenger side
- Try combination of BOTH.
Also, in the same color, draw a pair of "Darkest to Lightest" lines on the Sill, from fender to fender. You can try "1/6 size for top line : 1/3 size for white space : 1 size for bottom line), depending on the width of Sill. Instead of "1 : 1/3 : 1/6 ratio", you can use any other ratio like "1 : 1/4 : 1/8 ratio". Just play around
Note: The view in your photo is NOT ideal to know how car will look after modifications; take Low Angle Photos directly from front (like this one
here) and from side in day-light.