Spell Focus

Type: General
Source: Player's Handbook

Choose a school of magic, such as Illusion. Your spells of that school are more potent than normal.
Benefit: Add +1 to the Difficulty Class for all saving throws against spells from the school of magic you select to focus on.
Special: You can gain this feat multiple times. Its effects do not stack. Each time you take the feat it applies to a new school of magic.