If you have a plan, what is it?

Even though I do not have any unanswered college or career questions that apply to me personally, since I already know what major I will have, what college I will go to, and have seen my older brother go through college, I still have some questions to ask. This is because some or most of the posts that I have were asked or answered by people that indicated that they were not sure what college, if any they would go to for various reasons, did not know what career(s) or major(s) to pick(some people double major or do something similar with careers), or both. My two questions are "If you are going to college and have an idea of what you will do to discover your major or career, what will you do to decide what career(s) or major(s) to pick?" and "If you already have a career(s) or major(s) in mind and have a plan for how to get there, how did you decide or choose it/them?" I am not looking for any particular answer, but if you plan on double majoring or doing something similar with careers, please explain why you decided to have multiple careers/majors.