sharpies | scissors | parchment paper | washi tape (similar - mine is available in the office supply row @ Target)
It's a simple project, just creating a sticker sheet on a parchment paper backing by overlapping strips of tape, which you can trace shapes onto (I used cookie cutters as my stencils for these) and cut out. Then just peel up carefully and stick them wherever your heart desires. Here's how I did it:
The great thing about this tape, besides the fun patterns, is that it's like masking tape - peels up really easily, so you can stick it on glass or candles or even walls and remove it cleanly later - so it's perfect for some temporary decorating, like on a vase or a phone case or a mailbox if you want to remind the postman where to leave your love letters. The stickers would also be really cute on Valentine's cards, or as a closure on your honey's lunch bag.