I made my own, but here is what you should have:
1. Make them much wider than the windows on all sides
2. Mine are triple lined. This is also insulation, absorbing condensation, etc.
3. Have Velcro on the sides so no light leaks out especially on doors with windows that move and catch the wind. When two curtain sides join in the middle, have a strip of Velcro from the top to the bottom so it is comprehensive.
4. You can use close pins and hold on sunshields/reflectix also.
5. Make them in a classic, dark color and large. I have transferred mine from vehicle to vehicle for YEARS only doing all that work one time. I started with fabric I ordered by the yard from the factory that matched my cushions.
6. Make tie backs to match with Velcro for easy opening. Place the tie backs 4" or so from the end of the curtain, so when you tie it back the curtain is fully open for maximum light coming in.
7. For curtains near a fan or a/c unit, make sure they are long enough that when the fan is going, no one can see in.
8. Curtains on an angled wall should have a curtain rod on the top and bottom so the curtain is secure to the window, not a fire hazard, etc.
9. If you vehicle is not used during winter, do not store curtains in open position. Not only will they be very wrinkled, but a mouse may nest in them for warmth. Take out the sunshields, and open the roof vents some for winter cold, and let the curtains hang free by gravity so they are not a warm mouse bed.
10. The most important step: Turn on a 100 watt light bulb at night, walk outside of vehicle and check to make sure there are no gaps of light. This way no one can see you go to the bathroom, change clothes, or that you are alone.
