Glue a small piece of scotch tape on the tip of the needle.
When you minimize the bottom line should always remain at the same level, or rose "goes" is not in breadth, and in height (will not lush, but on the contrary, a long and narrow).
All internal "work" best done by thin nail scissors.
Determine the position of the place of flowers, too, must be in advance, so it's best to try them first, and then paste.
PVA glue is well suited for this purpose, especially when you consider that within the flower is already sealed by tape and remains only to fix free edges.
When design becomes fixed and completely dry, visible cardboard may be coated with any shiny nail polish.