About a year and a half ago (yes, I am that slow here), I made some blackout curtains for a room my girls would be sharing. The one moving in likes to sleep in dark rooms, so I needed to darken this bright place. The one who already had this room wanted pink curtains. I got the light pink and the dark pink to line, but it still let too much light through. My 7 year old son suggested I put a black between the two fabrics. So that is just what I did!
You can see it is just a large square large enough to cover the window. Then I use ribbons to tie it up. And over the last 1.5 years, I have gotten lazy about getting a chair so I can tie these things up each day. So I take one ribbon and tie it in the middle of the curtain (so the ribbon is horizontal) and it still let's through a lot of light for daytime. Hopefully you know what I mean by that.