Auto Ventshade makes it a snap.

The new Qwik-Snap Ventvisor®, slides into position without the use of tape or clips. It's made of an impact modified acrylic that can be easily installed or removed in seconds. Like its predecessor the original Ventvisor®, the Qwik-Snap version allows you to crack your window so you can stay dry in the rain and cool in the heat. Available in a smoke color to match other AVS accessories, the Qwik-Snap Ventvisor® is optically clear with no surface imperfections and is available for most vehicle makes and models.