Curtains, Feedback needed

One of the first things I did when we arrived was borrow Angie’s sewing machine and make some curtains for our bedroom window out of a white sheet.
My good Curtains
I am pretty proud of them, but they seem a bit plain. So I’m taking suggestions for what to do with them. I have a ton of ideas but am limited in resources (mostly because I don’t know the words to ask for most things).
They have to be able to close and open easily, because our bedroom window faces the parking lot but it is our only window and I like to have the light.
Maybe I should paint something on them, or find some colored thread and stitch some pattern or other on them. I just can’t get an idea that works for me. The best I’ve got is making a series of multi colored button holes and threading the ties through them instead of around. What do you think? Should I just leave them plain?