Once you have landed safe and sound in Boston, go through all the immigration paperwork and find a place to sleep; unfortunately, it is not over! There are still many things you should take care of so that you may live a relatively hassle-free life when you are here.
Do not worry! Below, I have listed a few things you should consider (e.g., banking, cell phone lines, transportation) and some basic advice that will save you some time figuring things out. Once the semester has started, you'll want all the extra time you can get!
Note that some of these concerns will apply more to international students than to U.S. citizens. Also, this is certainly far from a complete list of things to consider. Many other students are dealing with or have dealt with the same questions, so do not hesitate to ask your new friends, your mentor, or others for advice!