When you have the white primer completely covered with color shoot a couple more passes to doubly insure the coverage is complete. Before preceding with the clear coat it may be necessary to flat sand the color coat. If the color coat appears smooth sanding before applying the clear coats may not be necessary. Definitions are in order here. Overspray refers to paint on the surface that dried before it reached the surface.
Orange peel is caused by the paint drying before it flowed completely smooth and flat.
Orange peel will take more aggressive sanding. Sand until the surface is smooth and all the bumps are gone. When the sanding is finished wipe the guitar with damp towel to remove any dust. Now inspect the guitar. Check for thin spots where the white shows through and spots where the lacquer is drying into the grain.