Download the Star Wars Valentines you plan to use.
Print on lightweight card stock - make sure to choose 'black and white.' in settings.
Fold cards and use a paper cutter or scissors to cut down to size.
How to Make Glow Stick Light Sabers
Wrap a small piece of duct tape around the one side of a glow stick, beginning right at the edge. Repeat until you have as many as you need.
Next, draw lines and buttons onto each one with a black sharpie.
Attach glow stick light sabers to Valentines cards with tape.
Video
Notes
If you don't have an inkjet printer, I recommend having these printed at a print shop like Staples or FedEx Office. They can print high quality and it's really inexpensive, just make sure to select 'black and white' in the print options.