Preparations

Line a colander with two layers of fine cheese cloth.
Place lined colander in a dish (baking dishes work well)
Directions

Pour yogurt into colander being careful not to pull cheesecloth away from edges.

Fold edges over yogurt to cover and place in refrigerator overnight.

check thickness.  if you want it thicker uncover and pull yogurt from the edges gently tugging on the cheesecloth and fold gently with a rubber spatula and then recover with cheesecloth.  Return to refrigerator.

When the yogurt reached the desired thickness place in a air tight container.