Contact the DMV
When you were arrested, police procedure requires that the officer take away your physical driver's license, and give you a pink, temporary license. It says in big bold letters on that license that it's good for 30 days. But hidden in the fine print is a notice that you will suffer a license suspension unless you contact the DMV within 10 days of your arrest to schedule a hearing and ask for a "stay" on any license suspension! Most people focus on the 30 days, or their court date, and miss this deadline, which is bad, since that means the loss of your driving privileges.
You'll want to get a police report, and your blood or breath test, if possible. You definitely want to take advantage of an attorney consultation (most lawyers offer an initial consultation for free) and get as much information as possible on your defenses, and your rights, unique to your particular situation. You will want to know how this could affect your job, your insurance, your driving privileges, and your criminal record, and what you are facing overall.
Prepare for your court date
Whether you chose an attorney to guide you or not, you'll need to be prepared for your court date. Dress professionally, but not so much so that you'll be uncomfortable. Bring originals or copies of everything that was given to you when you were arrested (or released). Typically, you'll see a judge at your arraignment, who will give you time to get a private lawyer if you want one, allow you to apply for the public defender (if you qualify) or allow you to represent yourself (which is not recommended). Know what you want going in.
Investigate and evaluate everything
You can't do too much preparation for a DUI case. Visiting the scene of the field sobriety tests, looking at the patrol car video, re-testing the blood or reviewing the maintenance and calibration logs for the breath machine, are all steps that can lead to a dismissal of charges, and are worth doing. You can only make a decision in a DUI case if you have all the facts and know how strong or weak your case is up front.
Make a decision
At some point, the prosecution will come up with a plea bargain offer, typically. At that stage, you'll want to know what you want as far as goals in your case - and what's acceptable and what's not. Your options are to (a) Accept the offer; (b) reject the offer and go to trial; or (c) make a counter offer; and that's where your goals are important. If you're offered jail time, or a lengthy probation or alcohol school, or a criminal conviction that is too high for you, you need to either reject the offer and set the case for trial, or make a counter offer.