Heavy paper (I used watercolor paper but a heavy cardstock would work)
Paintbrush, Scissors, Tape
Step one: Cut your cardstock. Really, this can be whatever size works best for your paper, as long as it turns out to be an "I" shape. I cut mine to 3x4" with the divets a half inch in, and an inch from the bottom and the top.
Step two: Paint your cards. I painted simple layers of strips, using acrylics that I watered down to get the different colors. While one side dries you might want to move on to the next step, then come back and do the other side.
Step three: Paint hearts on your shoelaces. Hearts can be VERY simple when they are this small. I just painted one line at an angle (there is half of a heart on the lace above) then painted a line angling the opposite way on the other side. As long as the bottoms touch and the tops don't, it will look like a heart.
If you're going to paint black laces as well, you'll probably have to put down a white base then paint your pink (or whatever color you pick) on top.
Step four: Write your messages. If freehanding makes you nervous, trying writing it out in pencil then tracing it with markers.
Some message options:
You make my heart race!
Valentine, I shoe do think you are great.
Valentine, I like shoe! (eeeh)
You are my sole mate.
We make a great pair.
I'm head over heels for you.
I would walk 500 miles and I would walk 500 more...
Step five: Tape the middle of the laces down on the back of the card, then each section around separately, being sure to leave enough to tie a bow on top! And that's it, you're done! Now those shoe are cute!