I've taken to saving and recycling used blades as one-time glue applicators for fretwork - the flat ends of the smaller blades can hold a small and manageable drop of glue that, with a bit of practice, becomes fairly easy to track a narrow glue trail along the more delicate parts of the fretwork. After drying, if there is a protruding piece that needs more to secure it then I spread a small drop of CA gap filling glue on the corner of a piece of paper, slide it underneath, then remove the paper and secure the piece.
Jay