I gather up limbs and brush from the area of the blind, but be careful not to take so much that the hunt area is too open. When I trim the shrubbery at home, I take cuttings and pile them on. Now that Christmas is over, I will collect as many discarded trees as I can and add them. Over time the brush dries out and settles, so you will need to add to it from time to time. Make certain you pay attention to the backdrop
Also I am setting out Nandina (sp) bushes to grow a permanent brush screen. Also, I am planting Four O'clocks, a type of perennial flower that grows about 4 feet high. If that works out, my permanent ground blinds will require much less maintenance. Lastly, do all your blind work well in advance of the season so all the changes you make will look natural to game. Sudden, massive changes in your blind will be noticed by the deer.