Make sure your OWI attorney is well versed in drunk driving law. But don't stop there.
With regard to possible defenses, discuss the case in detail with the OWI attorney (rather than an assistant who screens calls) so that the attorney can properly and efficiently analyze your case.
Even if you believe a certain detail is not important, disuss it anyway and allow the lawyer to decide the relevance of it. Time is of the essence to prevent destruction or loss of evidence, and there are a wide range of defenses that must be considered. Something that may not seem relevant to one defense can be critical to another.
For example, if you were smoking on the night of the arrest, that fact will likely be irrelevant with regard to a blood test to determine your blood alcohol content, but it may be very important if you were given a breath test.
If you allow me to conduct a free case review on the phone or by email, I will provide you with my initial assessment of your case, and we may then discuss a reasonable fee for defending the case.