Inner Sight (one point)

Clvl: 1
Prerequisites: None.
Effect: Illuminates monsters and decreases their ability to defend themselves.
Properties: 13.3 yard radius, fixed cost of 5 mana, casting speed is subject to faster cast rates.
Synergy from: None.
Synergy to: None.

Slow Missiles (one point)

Clvl: 12
Prerequisites: Inner Sight.
Effect: Slows the missiles of nearby targets.
Properties: 13.3 yard radius, fixed cost of 5 mana, all ranged attacks slowed by 33%, casting speed is subject to faster cast rates.
Synergy from: None.
Synergy to: None.

Get in the habit of using these skills early. What makes them valuable is their ability to illuminate monsters but only one point should go into these skills, as extra points will merely lengthen their duration.

Let's start with Inner Sight: use it as much as you can, then as soon as you get Slow Missiles, forget about it. The extra DR reduction from Inner Sight isn't worth further investment because it's a straight value rather than a percentage, and slowing down missiles is a much more effective defensive measure. Multiple castings of Inner Sight aren't stackable, they simply restart the clock. However, if two or more characters use Inner Sight on the same monster(s), it seems to reduce the monster's defense with each casting — the total reduction is the sum of the two reductions.

If something, anyone, anything is shooting at your bowazon, cast Slow Missiles. Period. Carriage return. Slow Missiles is the amazon's best multiplayer skill and your best friend in Hell difficulty, where ranged monsters are a dime a dozen; it has many uses, like shortening the speed and effective range of Inferno, charged bolts (such as those from LEBs), and spells cast by monsters. A high-level Slow Missiles is extremely effective to use against missile-dependent characters (like bowazons) in PvP; if you've a dueling character somewhere, keep something with a couple of Slow Missiles charges handy. It only helps, however, if your bowazon actually gets out of the way of the missile. This skill isn't stackable; multiple castings merely reset the skill's duration. Note that Slow Missiles changes the speed of the missiles, but not the attacker's rate of fire.

If either skill is chosen, having an assigned hot key is highly recommended.