I will do the fuselage in sections. Normally, I do the bottom sheet, coming up the side a bit, then do the sides, and overlap the bottom piece a little. Same with the top. It is easier to do it in smaller sections due to surface geometry.
I apply at least one coat of clear to the bare wood, then sand lightly. If you try to put the silkspan on with no dope on the wood first, everything soaks in, and not much is left to stick the silkspan down. I will put the dry silkspan in place, spray with water, then dope thru the dampened silkspan, working the wrinkles out.
And, never cut the silkspan. Always tear it since that feathered edge is much easier to blend in and you never see the seams.