[Lox]

You raise your enchant skill by using enchanted items and by successfully making items yourself. I know its kind of a Catch-22, because it's really hard to make your own items. I suggest getting a lot of small soul gems and killing a lot of rats. Then practice making throw away items with small effects. These should be easier to create than the powerful items you will actually want to use.

For my character, enchant is a major skill, but it's still only around 60 (char level is in the 30's). I have amassed over 600k in gold, so I just buy my items. It's less frustrating.

As for enchanting a shirt, you do it just like you would do any other enchantment. You need to make sure that your character knows the fortify attribute spell (any attribute will do). You can only make enchanted items with spells that your character knows. Even if you buy it.