Legal malpractice attorneys will handle your claim against your former lawyer, if they agree that you have a claim. You must be able to prove that you suffered damages due to the past attorney's actions or inactions. Just because the attorney's losing strategy did not work out for you, this does not necessarily mean you have a claim.
In addition to suing your past attorney, you may also report his or her behavior to the proper state bar association. If the state bar decides he or she did commit some form of legal malpractice, they will be reprimanded accordingly.
If you believe you have suffered injury at the hands of a former attorney, contact a legal malpractice attorney to evaluate your claim. Often, the statutes of limitations for these claims expire quickly. These claims are an issue of one's state's laws, and they may change from state to state. Thus, if applicable, you should consult with a local legal malpractice attorney quickly to better determine your options available to you.