I failed to notice that the two windows in my front room/dining room are not the same height and that one window is 10 inches higher from the ground; because I'm super smart and observant. So the curtains I bought were too short.
I had some leftover fabric that matched the curtains so I decided to use it to add the needed inches.
The curtains I bought were 84" long, and the top of my window is at 90" from the ground. I wanted to hang the curtain rod higher than the window, and I wanted the curtains to pool a little at the floor. So I added 14" of fabric - making the curtains 98" long. I hung the rod at 96".
I do not sew or own a sewing machine. I did this whole project with iron-on bonding tape. It was really easy. I "hemmed" three sides of the fabric with the tape, and then attached the fourth side to the curtain with the tape. Done and done!