You'll find various enchantment "recipes" that you can take to enchanters who will use the gems and so on; these give weapons, armour and jewellery similar attributes to the charms, but they use different "slots" giving you a greater number of attributes overall.
Enchanters can also learn "recipes" by disenchanting already enchanted items: you'll come across quite a few of these in various loot drops, so take them to your local enchanter before selling them! A recipe is only learnt once so there's no point with identical enchantments, but keep an eye on its effectiveness before dismissing it as not being worth the effort as they are levelled.
In particular, keep an eye out for malachite gems: they're extremely rare and have useful health regeneration properties. Don't waste them, though: they're ideally saved until a bit later in the game when higher level armour and enchantments become available, and once they're used up, that's it: you don't get them back upon disenchanting an item.