Minors are basically unimportant - I've never been asked about one and I've never heard of one mattering the least in any application process, including job-hunting.
As for majors, I would say that there's only one thing you should look for:
Be able to explain why you are majoring in that field.
That's the crucial thing. Find a subject you are passionate about and be able to explain why you are passionate about it: do you find it important? Intellectually stimulating?
This is why I'd usually recommend against premedical students being, say, basket-weaving majors; it is hard to convince a medical school that that is a useful area to study. I'm an economics major; I've been able to explain (I think compellingly) to people how that links to medicine, how that plays into my interests, and why it's important to the world at large.
People will probably cut you some slack if you are a biology or chemistry major; they probably will not expect you to have a dynamic, interesting explanation for how that links to medicine.
To be honest, there is no rush to declare a major. Give yourself a chance to take a class or two in each of the fields you might be interested in. (I had already taken at least one course in each of public policy, political science, economics, biology, and chemistry before I settled on a major.) I hope you have plenty of time and a lot of classes before you need to really choose.
Find something you feel you can explain and defend enthusiastically when interviewed about it. Maybe that's psychology. Maybe it's biochemistry. Maybe it's something entirely different...
... but find something that you love, and something that will in some way make you a better doctor. If those instructions sound broad, it's because they are: take that freedom and use it fully.