Any size paperclip will do, when it gets fun is when you start making them in colors! The overall process is very simple, yet hard to describe in writing, so try looking at these photos (If anyone can't figure it out just send me a message and I'll do my best to add a walkthrough.)
Step 2: Stick 'em on stuff!
These work just as great as normal paperclips will, so go find some stuff that needs one (or ten) and share them! Happy Valentines Day! (-: