I'll be honest with you, I am a very lazy person. I hardly do what I should, so I am not example of the correct. What I do do is make sure that I am standing correctly, with my core muscles engaged. I mean, whenever I walk or stand, just anywhere, I think of engaging those low muscles that are kind of around your kidneys, and under your abdomen, on each side of the belly button. The trick is to learn how to keep them softly engage, and still breathe!
I don't have any cool advice, I only know that when I have trouble with stability, and I do a lot when riding the 17hh Irish sport horse, it's probably due to me not having and using enough core strength.