Yes, you are right, most of the management consulting firms hire any major. But one can argue that some backgrounds such as business, economics and engineering are a bit more common.

A lot of undergrad level hires end up doing quantitative analysis with a lot of data, so comfort with numbers helps, as well as sound business judgement. I would also recommend being active in leadership roles during college, these are desirable traits in a consultant to lead teams of consultants or clients.

Language skills would come in handy if you'd like to work in the country where the language you learn is spoken. Otherwise, it is not a big deal.

Another big thing is to prepare participate in the on-campus recruiting events and preparing well for the interviews.

Good luck!