Ground blinds are a great tool. And the previous suggestions are great. When I first tried my ground blind out, I learned that the hard way. I took a friend out on his first muzzleloader hunt. We sat in the blind together so that i could guide him on the proper shot placement, when to shoot etc. and to try to film. We saw 3 does way out in a field get spooked when the farmer fired up his tractor and I told me friend get ready cause I knew they would eventually get to us. Sure enough, when they got to 50 yards, they spotted the blind and were gone! Now when I use my blind I tuck it back into existing vegetation,preferrably with some overhanging branches that can be trimmed for shooting lanes, or brush the heck out of it.
But I would also add that nature can make great ground blinds. If you do not have the time to wait for deer to get used to a new blind or permission to cut, or would have to clear the forest for enough brush to hide your blind, blow-downs, old logs, cattails, a thick clump briars, can all make for a quick blind. The first deer I shot I was using a think group of briars with honeysuckle growing through them as my blind. I have killed several deer with a bow using an old ash log that sits about waste high of the ground and is covered in virginia creeper.
So brush up your groundblinds but don't be scared to use the one's nature provides as well. Good luck!www.deer30outdoors.com