Strafe is the skill of choice for many high-level Bowazons, although Multishot is also an option.
Strafe will automatically aim and fire at targets on the screen up to the Strafe limit. As you get more points in Strafe it will hit more monsters at once.
Strafe is good at alerting you to new monsters entering the area. If you start firing in a new direction where you previously have not been firing at, you will know a monster is over there in that new direction.
Try to lead groups of monsters into a tight pack. You will then be able to take advantage of Pierce. This will also keep you from switching back and forth in opposite directions which will save time.
Strafe isn't as good against a single monster as large groups of monsters. You may quickly run out of Mana when using shots against a single monster. Try switching to another skill if you are fighting single monsters.
Strafe will sometimes fire a little off-screen, but Multishot is much better for firing at monsters off-screen.
Strafe works very well with Cold Damage. Find an item that adds Cold Damage to make all your hits Cold Damage Arrows. This will chill monsters and will also sometimes shatter them preventing monsters from raising the corpses. Freezing Arrow also works well with Strafe especially in Normal and Nightmare mode before Cold Length is significantly reduced. You can also set one mouse button to Freeze Arrow and the other to Strafe (or use Hot Keys). Fire a Freeze Arrow to stop the monsters in their tracks, then follow up with Strafe to shatter them.
You may wish to assign Strafe to your right mouse button. That way if you need to get away, clicking the left button won't cause you to Strafe rather than move.
Strafe works with the Paladin's Concentration Aura in the following way:
Damage = Bow_Damage*(1 + Dex_bonus + Concentration_bonus + Strafe_bonus)
There is a rather hidden "Minimum shots" effect in Strafe. What this means is that Strafe will fire at least this many shots at one monster, but will fire more up until the Strafe limit if there is more than one monster. This is very useful in making multiple hits vs. one single monster, but the downside is that it puts you in Strafe lock more often.
The formula is as follows: Min Arrows fired = 2 + slvl / 4 rounded down.
Which means, at level 4, 3 shots are fired; at level 20, 2 + 20/4 or at least 7 Arrows are shot.
While you are Strafing, your character will be locked in place. You will be unable to move until you are done Strafing. Keep in mind that as you put more points into Strafe and it hits more targets, the time you are locked will be longer. Hardcore players might wish to avoid placing too many points into Strafe. For players on Normal mode this is generally not a problem. Be sure to not fire a Strafe right before trying to run away and you will usually be OK.