When referring to a person in a story:
* KAR-ik-ter (emphasis on the first syllable)
When referring to a person's personality:
* KAR-ik-ter (emphasis on the first syllable)
When referring to a symbol or letter:
* KAR-ik-tur (emphasis on the second syllable)
It's important to note that the pronunciation of "character" can vary slightly depending on regional accents. However, the above pronunciations are generally accepted.