whats the best way to hang stuff from this?

[Isaacey]

I have a 70% shade tarp.. its a tight woven plastic material.

[trilobyte]

Don't hang anything from the shade material, you hang it from the structure supporting the shade.

[TomServo]

If your going to hang anything under the tarp, I would suggest stringing up a "net" like series of ropes, under the tarp. Steel cables with turnbuckles (see image), if hanging anything with weight. The network of rope or cables will also serve as tarp support for downdrafts..sparing you lost grommets.

[Rice]

If you hang something on the shade material it will probably fly around when your shade structure is hit by a gust of wind. There can be a lot of gusts and they do cause most shade materials to move. I personally would not want something big and pointy flailing around every time the wind blows...

Use the frame to hang stuff... (either attach directly to your shade frame or suspend hanging lines between the posts in your shade and hang stuff from that.)

This can and does happen: