Pull over calmly and carefully
When you see those flashing red and blue lights in your rear-view mirror, take a deep breath, activate your turn signal, and pull over to the right as soon as it's safe to do so. Roll down the window and place your hands on the steering wheel so that they're visible to the officer.
Be pleasant and polite to the officer, but don't volunteer any unnecessary information. Give short, succinct answers to any questions the officer asks. Make sure your driver's license and car registration are easily accessible so that you can provide them to the officer without fumbling.
Politely refuse to take a field sobriety test
Field sobriety tests are completely voluntary, but police often neglect to mention this. Drivers sometimes think they can avoid a DUI arrest by "passing" a field sobriety test, but that almost never happens. Police use these tests solely to establish probable cause for an arrest and to generate evidence for a court case.
If offered a choice, select a blood test instead of a breath test
In California, you're generally offered a choice between a blood test and a breath test unless only one type of test is available. If you are offered this choice, always opt for a blood test. Breath samples obviously cannot be retained, but your blood sample can later be tested by an independent lab chosen by your defense lawyer. The technicians who analyze blood samples in DUI cases sometimes make mistakes, and an independent analysis may vindicate you.
Exercise your right to speak with an attorney before being questioned
Police are allowed to ask you basic questions during a traffic stop such as 'Where have you been?' 'Have you been drinking?' etc. However, you're entitled to consult with a lawyer before being questioned and to have that attorney present during interrogation. Unfortunately, it's sometimes difficult to pinpoint when a driver is actually under arrest. However, you can avoid any problems by declining to answer any questions until your attorney is present.