Hello and congrats on deciding to go for your MBA.
When I was going through the process I did thorough research. One of my main criteria was the reputation of a school. Since you will be investing tens of thousands of dollars in your education, it is most important to consider your MBA's reputation. Not only will it impress employers, it can also help you make alumni connections and their career center may have more resources to support you. Attending a smaller MBA program may be less competitive, yet just as expensive. Therefore, I recommend attending a larger MBA program so you have many more options after graduation.
Aside from asking peers and former professors from my undergrad, I considered the list on this page:
Business Schools Rankings - Businessweek. Please don't hesitate to reach out with any more questions.