You certainly will want to know about the attorney's experience in DUI matters. Prior experience as a prosecuting attorney is typically a plus, but there are many excellent attorneys available to practice in this field of law who have never served as a prosecutor.
I think it is important that the attorney is experienced in the courthouse in which your case will be heard. Even better, the attorney should be known to and respected by the judge who will hear your case.
You will obviously be concerned with the attorney's fee. Remember, you can usually find an attorney to handle your case for less, but I am a firm believer in the adage "you get what you pay for." Experienced lawyers typically command higher fees than newly minted attorneys. Keep that in mind.
If you have attorney friends, they may be able to refer you to a lawyer known to them as doing good work in this area. Friends may also be able to provide a referral.
Disclaimer: The information contained in this answer is not legal advice, does not establish an attorney-client relationship and is offered for informational purposes only. Individuals with questions or problems in any area of the law should consult a qualified attorney licensed to practice in the individual's jurisdiction.
Experience. Number of jury trials. Reputation and personality. Feel comfortable with him or don't hire
Ask specific questions about the law and procedures related to Statutory Summary Suspension, MDDP procedures and the DUI charge itself. (Filing deadlines, possible sentences, basis for motions...those types of questions). If the attorney is sufficiently experienced, you should be able to determine whether he/she really knows what they are talking about or not. Ask also about what the attorney thinks about the judge, county, district or courthouse where your case is assigned. As indicated by the other attorney, prior prosecutorial experience in the county where you are charged never hurts. And make sure you get a free initial consultation.
Years licensed, work experience, education
Peer endorsements, associations, awards
Publications, speaking engagements