I would call the police first of all but I would also be very careful and with a quick view of the scene I would make an assessment of how the person died. I don't mean to make it sound like I would make a medical diagnosis, but in general I would try to determine if it looked like there was a struggle, or is blood visible, or does the scene look calm and it appears as though the person died naturally. The reason I would try to make those determinations is for my own safety. If it looks like a murder scene that just took place, the murderer might still be there and I could be in danger. I would be looking for a place to get to where I could see what was going on but be protected against immediate danger. I would not touch the body or anything else so there wouldn't be a chance of tainting any evidence at the scene.