What to do at time of arrest
Never take a field sobriety test or a breath test if you have been drinking. This information will be used against you in your case. The less evidence you give them the better. Make no statements at all and if asked if you have been drinking be sure that you take the fifth amendment and make no statements.
What to do after the arrest
This is going to sound simple but you must hire an attorney before your arraignment. This will allow your attorney to make the appropriate motions on your behalf. Also there are many things that have to be done administratively to ensure you can get your driver's license back as soon as possible.