The second golden rule of hide making is to use a totally opaque fabric otherwise the birds will easily see movement within the hide. I favour a heavy, close-weave, green canvas. It's terrible to sew but, once made, lasts for years. My prototype hide is now in its seventeenth year of intensive use. The once green canvas has sun-bleached to a dirty yellow but the birds don't seem to mind at all.
Some photographers make hides from camouflage fabric.
Whilst this may have a slight advantage for animal photography, in my experience this makes no difference to the birds. It seems that as long as the human form is disguised, everything works just fine. The third golden rule of hide construction is to make the hide as small as possible. The smaller and less obtrusive a hide looks to the birds, the more readily it will be accepted. Although I am sitting almost at ground level, the hide is designed so that the roof is only a few centimetres above my head.