Motherboard-specific configuration can be found in the configs directory of the lm_sensors repository. All configuration files from the old www.lm-sensors.org website should now be imported, however the old website contains some additional information about the origin of the configuration files.
You can send your configuration file to the lm-sensors mailing list.
Do you have an ASUS board? Check out the ASUS formula hacking page.
Do you have a Gigabyte board? Is the reported temperature too high? Take a look at this ticket.
Don't know how to figure out the voltage labels and scaling factors? Take a look at this article.