Research. It is important to know the top programs in your field. If there is a particular chemist or faculty member whose work interests you, take that into consideration. In addition, select a program based on who you are as a person and what you need in your professional and personal life. For example, if you're a small town gal, select a school that is situated in a town suitable to your preference, or if you like to go out and socialize frequently, select a school in a trendy area that will enable you to do so. Think about your future and how strong the job market is in your area. Opportunities to intern and/or assist on research projects should impact which school you ultimately select. This is not an exhaustive list of things to consider, but I do hope it helps as you begin your search for a graduate program. Best of luck to you!