First, check out the attorney's track record.
Make sure your attorney has actually tried cases. The more cases he/she has tried the better. A successful history trying felony cases through acquittal is even better. Ask your attorney for a list of the cases he has tried. If the attorney can't provide you at least a couple cases within the last year or so you may need to check elsewhere. Case numbers, charges, and judges the case was tried before are helpful. It is surprising to me that so many attorneys advertise in the criminal defense arena but haven't tried even a single case. Or they may have not tried a case in over a couple of years. It is your responsibility to make sure the attorney you want to hire to represent you has a proven track record.
Talk to your Attorney
While most cases don't require an actual jury trial, it is important to know how many and how often an attorney tries cases before a jury. Ask the attorney for a list of the jury trials he/she tried in the last couple years. If they can't list names of cases and give a brief description it may be time to seek other counsel. I've been defending clients since 1993. Its amazing to me that most attorneys who I practice with have not tried even one single jury trial in those 17 years that I've known them. Unfortunately, the attorneys usually won't admit to that fact unless you specifically ask them. Just because an attorney has practiced for 25 years doesn't mean they have any trial experience. Your freedom is on the line. When choosing your attorney definitely caveat emptor (buyer beware) applies.
Ensure the Attorney will Prepare all the Fact Witnesses for Trial
Experienced criminal defense attorneys are not afraid to discuss all aspects of the case with their clients. In fact, a close relationship with my clients helps me not only understand what each client's needs are but also is a valuable source of information available to only the defense. Friends who may be witnesses to the case that were not interviewed by the police, family members who have a pre-existing knowledge of various witnesses relevant to the case are assets that have helped me win cases over the years. Sure, an attorney will have to spend significant amounts of time doing just this type of preparation before trial. But the benefits to the client's case are often worthwhile.
It is common that most people know another family that used a criminal defense attorney. Don't be afraid to ask how pleased they were with that particular attorney. If you know anyone in the criminal justice system (court reporters, police officers, judges, prosecutors, etc.,) ask them their opinion on the attorney. This general community opinion on an attorney is very valuable.