Hi,
In all things to to with building and flying practice, practice, practice. The sticky by Minn at the head of this section gives great advice on finishing with plastic films and practice, practice, practice. Faye's book also is a great tool and practice, practice, practice. It helps if someone shows you one on one and practice, practice, practice. Get my drift

?
Given you are used to glass and paint when covering with film the surface has to be perfect
before covering. The smallest imperfection will show through but you are probably the only one who will notice.
Good Luck,
Colin