 Yeah, start inside by checking the ceilings on upper floors for any stains or other signs of leaks. And by the way, you ought to pay special attention to the ceilings above bathrooms and kitchens because that's where plumbing vents will actually pass up through the house and up through the roof above these rooms, and they often break down causing leaks. So also check for leaks above fireplaces, another spot where loose flashing can allow rain to seep in.