Be sure to Brush In Your Ground Blind with any type of tall grass,corn stalks,Cedar Tree limbs that is around or close to where Your Blind is set up...in other words blend Your blind in with whatever will look natural in the Area Your Hunting.I usually spray down my blind with some type of scent-killer or leave it out in the rain a few days to wash off any un-natural smells and scents off of it.
If Your blind is dark/black inside it may also help to wear dark colored Camo to hide any movement You may make and as stated don't leave all the windows open where You can be silohetted/outlined and the Deer can see movement inside.