Before visiting any field office make sure that you know about their timings and if they are open on the day of your appointment. You can find this information on the following page.
According to the USCIS, the size of the offices is small so “only the people who need to attend should come.” In case you need help with understanding the interviewer, you should arrange for an interpreter who can help you via phone.
If you need disability accommodation for the appointment, you can request it from the following page. The application is a form you fill and submit online.
The federal agency also recommends that you come only 15 minutes before your appointment. Also, if you’re late for the appointment, then you’ll have to reschedule, which you can do by calling the contact center. There are no charges for making appointments.