Based on over 25 years defending people accused of all sorts of crimes, here are my top 5 suggestions if you are stopped for DUI (or any similar offense):
1. Be polite but consent to nothing.
2. Give your name, required paperwork, address and the like if asked, but politely decline to answer any other questions or do anything "voluntary" unless the officer says you must.
3. Politely decline any so-called roadside tests (including the portable breath test sometimes given during the roadsides) then ask if you are free to leave and if so, be on your way.
4. If you are arrested and requested to submit to a breath or blood test, you could lose your driving privileges for a while if you "refuse." That decision is up to you, knowing otherwise that lack of a test makes it much harder for the prosecution later to get a conviction for DUI. If you decide to submit, choose the breath test (though it is easier for the prosecution to prove compared to the blood test, it is easier for the defense to attack).
5. Do not admit to drinking, to driving, or answer any voluntary questions about where you have been, what time etc. If you try to explain, you are only needlessly giving away information. Silence on these issues is your right, and silence is golden.
Not all lawyers would agree with the above and of course every situation is different. However, often when you read about a judge or police officer or prosecutor arrested for DUI while not on duty, these are the very suggestions they follow (although they seemingly almost always refuse to submit to a test). In my experience, not following the suggestions above makes it much harder to defend against a DUI charge that may be bogus to begin with.