Ahhh! Gravel driveways ! My favorite thing . As already stated you need to cut out the humps and bumps of the wash boarding or they will just come right back . Place your blade in the cut position (rolled more forward) and slightly angled . After you have cut out the washboards ,potholes or bumps you will need to remix your rock and fines so the gravel will stay in place . I do this by rolling my gravel back and forth a few times to get it remixed.
If you have drainage ditches that also need cleaning or repair ,you need to pull these first before grading the road . Once I have my material windrowed to one side of the road ,I set my blade for the road crown I desire and slightly angled . I then slowly pull the gravel across leaving the desire thickness . With practice you will run out of gravel or leave a very small windrow when you reach the other side . Then pack it down with your tires or a roller for a nice looking finish that will last quite awhile .
Don't forget to wheelroll the ditches if you can . This will help to seal them .
It helps if the gravel has some moisture in it as this will help the rock and fines to stick together .
Remember all roads need a crown ! Standing water is the #1 failure of roads !
Be careful grading in late fall or winter as you can break through the hardpack and end up with a giant mudhole . I usually do my grading in the spring or early fall .
Have Fun,
Big Al