In all honesty, I am not sure I can easily answer any of your questions, but I will see what I can do...As I have not used a P500 and rarely do any video even on my phone, I will leave the video out...
Vibration Reduction is designed to help provide a steady image when you are hand holding the camera. Do not use it on a tripod as you can sometimes get worse results.
Best aperture, best ISO, the easy answer here is "It Depends" Every shot is different and unless I was standing there with you, I couldn't give you a blanket answer. In general, stay away from the extreme ends of the aperture since they tend to magnify the limitations of any lens. ISO - keep it 400 or under if at all possible to avoid grainy images...some will tell you 200 or lower, but that isn't always practical.
Your best bet for the calm, natural look is to learn to shoot and learn post-processing. Read through your manual and then experiment. Get comfortable with how it works and understand when nature may fool your camera's meter so you know when you need to adjust and when you can adjust.
I don't know of any secrets to it, perhaps a book on the camera and / or a book on photographic techniques might help you learn some of the specifics of your camera model or photography in general. For any of the settings you may not understand, the manual or the above book ideas may answer your questions but feel free to ask about specific settings as we have a number of excellent, knowledgeable photographers here who are happy to assist.