1. Not taking the matter seriously. A DUI charge will follow you forever. It's worse if you're convicted or plead guilty. The thousands of dollars in insurance surcharges alone make the matter worth taking very seriously.
2. Not hiring an attorney. You need competent representation. The law is complex even for most lawyers. You will need to identify the right defenses and raise them at the right time or you will lose them. Witnesses vanish, facts evaporate and memories fade. A winning case can turn into a loser quickly.
3. Hiring an attorney based on the amount of the fee alone. The State of Oregon has unlimited resources when it comes to prosecuting your case. A qualified Oregon DUII defense attorney will need to be paid a fee which will allow him to put time and effort into your case to counter the prosecution. Your attorney must earn enough to keep an office open and make a living wage. If you choose a low-priced lawyer, that lawyer will probably not be able to spend the time necessary to protect you. That's just the way it is. You want to look for reasonable and predictable fees, not the lowest.
4. Not complying with Oregon's driver's license laws. You could lose your right to drive. For example, if you are suspended for any reason, including DUI, you must pay a restoration fee to the DMV. Your driving privileges will not be restored until you do this.
5. Driving on a suspended license.
6. Not taking complete, total and full advantage of your constitutional rights.
7. Just pleading guilty. Anyone can do that. You can't win if you don't challenge the charges. If you just plead guilty, you deny the the judge an opportunity to rule on constitutional challenges and you give up your right to raise these issues and make the state prove it's case.
8. Failing to appear in Court. The court will issue a bench warrant for your arrest and revoke any bail if you don't appear in court when you're scheduled to be there. If the judge orders a warrant, the next time you're stopped for a traffic infraction, you will be spending some time in jail and posting bail for your future appearances.
9. Talking to anyone but your attorney about the case. Anything you say to anyone but your attorney can be used against you.
10. Thinking that talking to numerous attorneys will give you the information that you need to handle it on your own. It won't. Not even close. You need to have an experienced DUI defense attorney go to court with you.