All advice given is good. I think the only thing I would add to that is to get your bow shooting as quietly as possible.
That, and make sure the deer isn't watching you when you punch that release. I was watching one of those hunting shows on tv today (yeah, I know), and this guy lets loose an arrow at what he said was 45 yards at a bull elk that was staring right at him. I was really surprised that he hit the animal at all (let alone make a pretty good shot).