Examine internal contradictions - google anachronisms in the book of mormon. The reformed hieroglyphics 300 years before Jesus using the words "Jesus" and "Christ" (both based upon greek). or French "au due".
Perhaps the 4000+ changes to the text of the book of mormon, said by smith to be the most perfect book in the world - corrections all done without benefit of the metal plates.
And finally, research HOW the bom was translated. True history records smith with his face in a hat looking at a smooth pebble (seer stone), no special glasses, etc. Check out www.mormonthink.com for more background.