One of the most confusing things about a hunter's repertoire of spells is the exact use of Auto Shot. This ability is unlike the abilities of any other class, quite different from a warrior's swing timer, or a caster's wand shooting. Auto Shot is like a metronome, and the music of hunter DPS requires that we play according to its beat.
We've discussed Auto Shot a little bit in last week's introduction to Shot Rotation, but Auto Shot is much more complex than is first apparent from simply reading the ability's tooltip. First of all, there is a discrepancy between what the interface shows you of Auto Shot and what is actually going on. If you don't use any hunter addons, you may have great difficulty getting a feeling for any of what this article is about, because Auto Shot doesn't have any representation in the default UI. If you use an addon like Quartz or ZHunterMod, however, you'll be presented with a timer that looks something like a regular casting bar -- and while this Auto Shot bar will help a great deal, it is still not complete. No matter what, your imagination and inner sense of timing are going to have to do a good bit of work in getting your shots timed right.