Treat each surface as it's own entity...ie; block the surface of the fender/quarter at the flat, then the lip/or flared portion on it's own...then the face of the wheel opening. You will see everything begin to blend together.
Try not to use your hands without some kind of sanding pad, as it will leave finger marks. But it WILL be necessary in some areas. Try to keep those areas as small as possible, however.
You can get different blocks made for specially shaped areas, but I find that if you have enough practice and watch, the old fashioned longboard will win out.
I tell all my trainees and painters "the longboard never lies."
Remember to use guidecoat

 

i was told by len at autobodystore to use a light colored primer and 'dust it'... since im painting it black and using black primer

 

NM