My son's room has some nice curtains from the previous owners of the house and they worked with his crib bedding so we kept them. The only problem that I ran into this summer was that it doesn't make the room dark enough. With it staying lighter later it was impossible to get him to settle down to go to sleep and naptime wasn't any better. That is when I decided I would just line the drapes with blackout material. They were fairly simple drapes and it didn't take too much time to rip out the seams and add the lining. I wanted them to look like they were lined in the first place and not as an afterthought. It worked perfectly and now it is so dark in there it makes putting him down for naps and bedtime a breeze. Here's a closeup image of the material.
Here is how big of a difference it makes to have the curtains lined with the blackout material. The first picture is with both drapes pulled back.
The next picture is with one drape pulled to the center.
This picture is with both the drapes pulled, but the hallway light is still on.
Hallway light off. Nice and dark!