To convict you of tax fraud, the prosecutors must prove that you acted willfully to evade paying taxes. There are several different types of tax fraud from not filing tax returns to providing false statements to refusing to issue W2s to your employees. The right defense varies based on the alleged crime and the situation.
Generally, criminal tax attorneys will try to establish that you did not have criminal intent. The prosecutor will try to prove beyond a reasonable doubt that you committed a crime, and your attorney will try to create doubt that you committed the crime.