There are generally three possibilities. You can appeal to the Board of Immigration Appeals, you can move to reopen or you can move to reconsider. An appeal is best suited for complex legal arguments, especially when there's legal support for a different ruling. A motion to reopen is suited to when new evidence has been discovered. A motion to reconsider is best when the USCIS has overlooked something.
But be aware that the filing costs run several hundred dollars usually, and there is no guarantee of success. You should always consider if filing a new petition is possible, and will provide a better record. This is especially true where the evidence submitted is thin.