Take your piece of paper.
Fold where you need to.
Place on edge of table.
Rub the fold on table edge until the fold is flat.
Flip over and fold across previous line.
Do the same as in step four.
Unfold. The paper should have a fine, flat fold.
Tear a small rip on one side.
Place hands on either side and firmly pull apart.
You now have two pieces of paper. :)
A little rough around the edges, pun intended, but gives it a "rustic" feel. ;)