Those trained to use Light Armor make more effective use of Hide, Leather, Elven and Glass armors.

Use this tree if you are a thief character type or assassin, or ranged type like ranger, since you want to move fast and heavy armor slows you down. Mages can consider this tree, but if you are  a pure mage you will most likely wear robes which are NOT considered light armor.

Increase this skill by taking damage while wearing light armor. Talking to light armor trainers can also level the skill.

TRAINERS

Journeyman Trainer: Scouts-Many-Marshes (Windhelm)
Expert Trainer:  Grelka (Riften)
Master Trainer: Nazir (Dark Brotherhood)

PERKS

Agile Defender (1/2/3/4/5)
Increases armor rating for light armor by 20/40/60/80/100%
Requires: Light Armor 0/20/40/60/80

Note: If wearing light armor, spend points on this perk as soon as you can

Custom Fit
25% Armor bonus if wearing all light armor: head,chest,hands,feet
Requires: Agile Defender, Light Armor 30

Note: Stacks with agile defender. You should be wearing all light armor anyway (no good reason to mix with heavy armor) so take this perk.

Unhindered
Light armor weighs nothing and doesn't slow you down when worn.
Requires: Custom Fit, Light Armor 50

Note: Very useful to rangers and to assassin/thief class characters

Wind Walker
Stamina regenerates 50% faster in all Light Armor: head,chest,hands,feet
Requires: Unhindered, Light Armor 60

Note: Take this perk when you can, as it lets you regenerate your stamina faster

Matching Set
Additional 25% Armor Bonus if wearing a matching set of Light Armor
Requires: Custom Fit, Light Armor 70

Note: Take this perk, unless you like to mix and match your armor pieces

Deft Movement
10% chance of avoiding all damage from a melee attack while wearing all Light Armor: head, chest, hands, feet
Requires: Matching Set or Windwalker, Light Armor 100

Note: Excellent perk that gives you a chance to avoid damage from a melee attack entirely.