Flatten out one of the coffee filters.
Fold up the bottom to meet the top.
Fold in half again to create a triangle shape.
Cut the side of the triangle off to make a square.
Open the coffee filter back up, it should now be a square. This is now a prepared tea bag.
To fill the tea bag: make two small piles of tea towards the center of the bag.However much tea you use, will determined it's strength. Start with 1 tsp of tea, split into two ½ tsp piles. Fold the tea bag into thirds by folding up the bottom ⅓ the way, and then folding the top down over that bottom fold.
Rotate the tea bag 90° and fold it in half, with the fold at the bottom, an the opening at the top.
Take one of the cotton strings, fold it in half and twist the fold together. This will help keep the string together while attaching it to the bag.
Fold the top corners of the tea bag down, into a gift tag shape.
Place the twisted string onto the top of the tea bag with the untwisted side facing out.
Hold the string in place and fold the top of the tea bag down with the string inside.
Fold the top down once more.
Staple the top in place, making sure to catch the string in the staple.
Add a tag or label to the other end of the string if you would like.