Research the company. Prepare a list of questions to ask the interviewer. Practice answering typical interview questions. Practice answering questions about your immigration status. Practice your speaking and understanding of English.
Assertiveness is an absolutely critical skill needed in the interviewing process.
It is acceptable to ask the recruiter to repeat a question, a phrase, or a word that you don't fully understand. Don't be embarrassed. If a recruiter seems confused by something you say, offer to clarify. Repeat or rephrase the statement as necessary. At a minimum, be sure to mail an appropriate thank you letter to the recruiter who interviewed you and everyone you met.