Explore the different options that are available to you. Look into the admission requirements (some programs require several years of work experience), the schedule of courses and the style of instruction. If you can, attend a class to check it out.
Find out if your company will pay for all or part of your tuition. It doesn't hurt to ask. Also make sure to ask what you owe the company if they do pay the bill.
Apply to programs that interest you. In some cases you may be able to take classes before entering a program.
Choose a program based on what it offers including specializations, curriculum, financial aid, future earning potential, networking opportunities and convenience.
Study, develop your skills and work in teams on the way to earning your MBA. Use your group assignments to network with your teammates. Part time MBA students need to work to compensate for the networking advantage that full time students have.
Use your new skills and knowledge during your day job, too. You will get extra practice and retain it better after the classes end.