First off, I used white kona fabric as the main piece. It has a nice weight, but I wanted it a bit heavier, so I sewed 2 pieces together. This particular curtain is 18" long and hung 7" above my windows (to give illusion that windows are even bigger than they are) on cafe clips (if you aren't using clips and need a pocket, you will need to add significant more fabric to include that). I sewed the 2 pieces of white fabric together along the top. I then flipped them over at the hem and ironed and topstitched, so you have a nice hem at the top. Leaving all 3 other edges raw. The contrasting fabric pieces are 4.5" wide and I cut one for each short side, adding an inch or 2 to turn under at the top, and then I cut several strips and sewed together til I had a strip a few inches longer than the bottom long edge. Now I sewed the side trims on first. Doing so, you fold down an inch and pin along edge as seen in above photo and you can leave the bottom edge raw.
Now sew along the edge.
Now turn the fabric over to the other side and turn under hem and sew along the edge of contrasting fabric. This is what it should look like when done on the front.
Here's what it looks like on the back side. Repeat this step for other short edge.
Now take your long strip and use the same process, except you will need to fold under both edges.