From what I did last beta (no I saw or I heard but I really did so I'm 100% sure ) here is what I know about jewelry and enchanting :
You cannot craft Jewelry at the moment, it was also said in the last Q&A with Paul Sage that they were looking into adding Jewelry to the craftable items.
You are given Jewelry as quest reward from time to time.
I don't know if you can get jewelry from loot on enemy bodies or chests I don't remember getting any but I may have forgotten.
You can enchant some of the rings and necklaces you are given but not all, for example the ring you may given after finishing the intro in Cold Harbor cannot be enchanted but I got an additional ring and necklace taler on that I was able to enchant.
Weapons and armor can be enchanted, the difficulty is to find runes to create enchants for them. Armors specially can only have enchants that give bonuses to max health, magika and stamina and those don't drop very easily.
You can enchant any item crafted or looted that doesn't already have an enchantment on. Traits are not enchantments and you can absolutely apply an enchantment to an item that already has a trait.
The difficulty is that when you see properties on an item it's not always easy to know if one of those comes from a trait, an enchantment or something else. That's why it's easier with items you craft yourself, you know what's on them.
Regarding enchanting here is a very very useful page that helped me understand what was going on and how I could craft the enchants I needed :
http://tamrieljournal.com/crafting-and-professions/enchanting/
Hope this help