1. When questioned for DUI before arrest, you are not in custody for the purposes of Miranda warnings. If you politely refuse to answer any of the cop's questions concerning the DUI investigation, either before or after the arrest, then there won't be any statements that can be used against you in court.
2. Field Sobriety Tests are completely voluntary. If you perform them, you may be arrested anyway. It may be better not to give the cop evidence that will be used against you in court. You can politely refuse to do the Field Sobriety Exercises.
3. Refuse to take the preliminary alcohol screening test. If you are older than 21, the test is voluntary and you have the right to refuse this type of breath test.
4. When given a choice of blood, breath or urine test after arrest, choose a urine test if it is available. It is the most unreliable; however, the officer may only offer a blood or breath test.
5. If no urine test is available, choose a breath test. The breath machines are not 100% accurate and there are many possibilities for error.  See California DUI & Drunk Driving Defenses to San Diego County Breath Test.
6. Contact a friend or relative from jail as soon as possible so they can hear you speak and note your state of sobriety.
7. Always be polite and respectful to the police officers. How you are perceived by a jury is extremely critical.
8. Some jurisdictions video the arrest, breath testing and/or booking process. Always be on your best behavior.
9. Make a detailed list of all the events before being stopped up to and including being released from custody.
10. Retain an experienced DUI/DMV defense attorney to represent you. Only an experienced DUI/DMV defense attorney is able to spot your favorable issues and present them to prosecutor, judge , jury, or DMV hearing officer.

Remember, the best way to avoid a DUI conviction or DMV suspension is to not drink and drive. Purchasing a Portable Breath Tester will also assist you in determining your alcohol level before you drive. Unfortunately, the way our laws are going, even if you've had only a small amount of alcohol and you are not impaired, as long as you smell like alcohol your chances of being arrested are very high. However, being arrested for DUI does not automatically result in a conviction or loss of your driver's license. Protect your rights and save your license. The above Top 10 tips are designed to provide accurate and authoritative information. It is not designed to render legal opinions.

Source - Myles L. Berman