I use the method Richard describes in this Partial Duplication video and it works great.  However, I tried another method using the Wizard that might be suitable in cases where only a few of many fields are not to be duplicated.
The Wizard creates a macro that duplicates the entire record.  You can simply edit that macro and set the Property Values to nothing (leave the Value parameter blank) for the fields you do not want to duplicate.  Seems to work fine.