Would start with the "classic" prep books: case in point by cosentino, victor Chang and then all PDF books from consulting clubs of MBAs you can get your hands on (hint: look at previous questions here asking for materials to find useful links).
then I would use the websites of consultancies to get their case and test examples.
finally I would first ask mock interviews to current employee as a key step in your preparation (especially if you know any, but ok tocold write LinkedIn messages). And then for the ultimate real experience I would suggest to book a couple of sessions with experts here. I would look for and choose the ones who were interviewers of your consultancy of choice and that had the most recent experience.
hope it helps,