After you learn Enchant Weapon, clicking on an equipped item with a charm quality will open up a charm window that you can drag and drop charms into (the number of open slots is up to the level of Enchant Weapon). Charms can not be removed once inserted.
The survivor's Curse spell is better than the mage's Withering Curse, since it can not be resisted.
Curse + any elemental attack is effective, as is Blind + Hell Spikes.
