Do a little research on the different housing options available to you. What does a suite in Smith look like? How big is a double in Arnold? What theme communities are available? Look around at all of the buildings to get a sense of what living there would be like. Also, the simmons.edu/reslife site has new features that allow for virtual room tours including photos and video if you don't have the chance to see them in person.
Have you heard of the availability spreadsheet? Use this feature of the reslife website to see how many rooms in each building are available. Speaking of the website, use it! It offers some really great information about housing selection that would most likely answer your question and also any that you didn't even know you had.
Don't have a roommate? Don't worry. Plenty of us experience this, and so Simmons offers many ways to find others looking for a new roomie! Attend Pair Fairs, join the Facebook group, or go to a suite matching fair. Even if you strike out with these, there is the Meet and Greet area at housing selection night.
Talk to your friends and find out everyone's' plans for next year. See where other people you know are planning on living and maybe make a plan to live in the same building. A feel for where everyone else is living can help you make plans for the upcoming year!
Drink a cup of tea, listen to music, the point is to relax. Housing selection should not be a stressful time. Have fun looking forward the next year