Foreign students with student visas in the United States faces so many problems in America. One of the major problems that they have to face is the language barrier. For example, a student from India with student visa will have a hard time understanding the professors even if he knows English because of the accent differences. Not only that, he will also have problems even expressing himself. Not every foreign students are comfortable talking to the American because of the low self-esteem. But the good news is that this language barrier is temporary and it will get better as you continue to go to classes.
Another problem that most students face is the cost of the books. Foreign students are used to buying books using their own currency but when you buy books in America they are pretty expensive. Now you might think about buying used book but these days professors would like you to buy the latest version every semester. You can use the library books to deal with the book cost but that means you will have to be in the library most of the time since most of the librarian don't allow class textbooks to be rented out.
Semesters and syllabus system is also different in America, which means you will have to get used to the American education system. 99% of the time your home countries syllabus and semester system wouldn't be same as the American system. So you might struggle in the beginning but it's not that hard to get used to the American system after living here for a bit. The good news is that professors in America are really friendly and they will be helping you as long as you need. Now, the exams systems are also different in USA. Many of you are probably used to lots of board exams in your foreign country but when you come to America, most of the exams are given by your professors. And the good news is that the exam materials are from the lectures. So if you attend the lectures you will be fine.
I guess these are the most common problems foreign students have to deal with as soon as they start classes in America. If you attend all your classes properly and participate and ask for help, you will be successful. Usually, professors are extremely friend in America and they love it when a student asks for help. Moreover, keep in mind that foreign students are more successful in America because they want to work hard and they are pretty smart compare to the American students.