Search the Internet for the keywords "top MFA programs in creative writing." Many sites will pop up. The Atlantic Magazine has featured top schools in the past so that is one place to look. Newpages.com also offers extensive lists of both traditional and low-residency programs. It is hard to rank these studio programs, though, which is why AWP (the Association of Writers and Writing Programs) refuses to do such.
Pick 20 or so schools to research further. Make sure you check out the faculty (and that they actually teach). Some schools boost popular writers on their teaching staff but they rarely teach. Also check if the school has their own literary magazine or an associated university press. These can offer great opportunities for internships and teach you about the publishing side of writing. Some schools require their graduate students to teach a course or two, such as Louisiana State University and University of Houston, while others are strictly studio based, such as the Iowa Writers' Workshop.
Start narrowing down your field. It is recommended to apply to at least five to 10 schools to help ensure acceptance somewhere. Make sure you've looked over all the information and are confident these are the places you would like to attend for the next two to three years.
Time to narrow choices down more. Do you want a traditional two to three year studio program which often offers teaching opportunities and fellowships, or do you want to try a low-residence program, which allows you to work full-time and study part-time in the evenings from your own computer? These types of programs typically have low funding options, meaning more student debt. Both have advantages and disadvantages, so it is up to you to decide which option best suits you.
Decide whether you want to live in a big city, such as New York City, or a small college town. There are a lot of good schools in both types of places, but if you are happy in your environment, you may be more likely to finish the program.
Prepare how you are going to pay. It costs money to apply to schools, and then you have the cost of tuition and living expenses. If you don't have the money on hand, as most Americans do not, you can take out a student loan. But keep in mind the loan will have to be repaid and writers typically are not that highly-paid. So you might want to look for a school that offers full funding. Some will even offer stipends for you to attend that university in the first place. Some schools which offer full aid include Louisiana State University, University of Houston, University of Virginia and University of California at Irvine. Keep in mind that to receive full funding and stipends, there are teaching and often other requirements.
Fill out applications. You'll need to send in writing samples, which are by far the most important, GRE scores, letters of recommendation, transcripts and of course your application fee.