Step1
1. Get an attorney. The money you spend on an attorney will likely be less than the penalties you'll end up paying. An example of places to get attorneys are here: http://www.1800dialdui.com/
Step2
2. Review what happened, be thorough. Know some important facts on what actually is defensable in your state. For example, these are some common things that can be used to defend your case (from http://www.1800dialdui.com/CM/Custom/TOC40WaystoBeataDUI.asp):
a. illegal stop of person or vehicle
b. weaving inside a lane is not illegal
c. anonymous report of drunk driving
d. field sobriety testing is inaccurate
e. non-standard field sobriety tests are invalid
f. breath testing is inaccurate
g. in squad videos
h. failure to provide speedy trial
(the website lists a total of 40, it's a great resource)
Step3
Understand how BAC works and the limits in your state. Even though you are not above the legal limit, officers can use their judgement to incriminate you if they feel your are too intoxicated to operate a vehicle.
Step4
Be courteous throughout your process. Manners will help, or moreso, bad manners will not help. There are alternatives to jail, a skilled attorney can help with them. These include:
a. work release
b. work furlough
c. electronic monitoring
d. city jail (for a limited stay, like 1 night)
e. alcohol programs
f. sober living facilities
Step5
Good luck, in the end it is most important to get an attorney right away that is an expert in DUI laws in your area. I think it is critical to have a specific DUI firm that specializes in DUI instead of more general criminal defense.