Many others replying to your inquiry hit many good ideas, but they missed one point. PRACTICE from inside the blind while seated!!! You will be amazed at how things change while seated and on ground level. Another thing is, look at how close your arrow is to your line of sight but not be able to clear the edge of the window upon its flights path. Don't ask me how I know this!! LMAO!!!
That and have fun. You will be amazed at how close will get to your blind once you get how to use it. My wife and I have had deer walk within 3-4 yds of it while hunting together.