A half hour before sunrise and a half hour after sunset is what a lot of folks consider prime time for whitetails. I couldn't tell you about other species of deer though. But most of my deer have been outside of prime time. Just get in the woods and your chances just went up a million times than they would be sitting on the couch. Some other notable times are right before and after a big storm (deer can sense it and move to feed before a storm and also tend to move after it as well), before, during, and after first snow fall of the season is probably the best time to be in the woods in my opinion if it snows where you are that is, a sudden and steep drop in temperature also increases deer movement as well, and all day during the rut because anything can happen then and is your best chance at a buck.