Is off campus internships hard? what are the best practices one should follow to get a internship offer from FAANG?
Hard or easy is a very relative terms. But if you study the scenario then year! Off campus interviews can be tricky for students as the variance of knowledge or result or standards can be observed with deviations in off campus interview. For example, if your college have 50 student and the distribution of marks they will get and based on the knowledge they have, they will be selected. But in off campus interview there can be a student who have done his/her Masters from IIT's (lets suppose) then you will have to compete with him/her can be bit stressful as you know the tag IIT's can be prioritized by the panelist. Although this is contrary to experiences. Thus there are no such hard or easy thing, everything is dependent on the moment on your knowledge and your skill.
For Internships you didn't mentioned your area you want to work in. But in general the suggestion for getting internship is that you should try to get some as much industrial knowledge as you can in your college life and focus more on skills. If you can acquire skills, you will never be left jobless.
I hope this helps.