I know everyone probably made about 100 of these in their pre-teen years. I have a distinct memory of sitting on the grass at recess making these with my little girlfriends ...
I love the idea of making something pretty out of weeds :)
Anyways, here's how I do it ... (please share if you have a different method!)
Start with three clovers ... preferably with loooong stems.
Braid the ends (just like you would with your hair.)
Insert the next clover in one of the braid "holes."
Keep braiding with this new stem (making the chain longer).
Keep going with this process ... inserting a new clover and re-braiding it into the chain.