If I had to name the single most common deficit among bowhunters who repeatedly fall short of their potential, it would have to be negligence, or ignorance, of the many ways wind can either help or hinder hunting situations. I remember a farmer asking us why we entered the patch of woods behind his house from different directions on various days.
As mentioned earlier, wind direction has a great influence on deer movement. Deer will move with the wind, across the wind, as well as into the wind. However, their preferred movement is generally into the wind so they can smell any danger well in advance.
Setting stand locations to take the wind into account is a good idea. Generally, during normal, stable weather, the wind comes from the West or Southwest. High and low pressure systems de-stabilize the wind and allow it to move in predictable, but different directions.
Understanding wind direction in relation to weather systems is an advanced hunting skill that may take years to master. Checking the hourly weather forecast on the Internet for the area being hunted just before the planned hunt is a good idea to help stand selection. However, local terrain will effect the actual direction; do not be surprised if the wind is slightly different than predicted. Bringing a notebook to record the actual wind direction verses the predicted direction will help advance your learning process.
As mentioned earlier, if possible, locate your stand downwind from where you expect the deer to travel, i.e., the deer is upwind from the stand.
In hilly or mountainous terrain, winds can predictably change during the morning and afternoon. The cool overnight winds flow downhill until the sun warms them and then they start flowing uphill; this process is reversed in the evening when the sun is not as strong, and the winds start to cool and again flow downhill in the late evening.