Have you've been holding your camera wrong the WHOLE time!?
How do you hold yours for a vertical portrait? I see a lot of people holding their camera like this:
Let me tell you the problem I see with this stance - the flappy elbow! Holding your right elbow out like this means you're more exposed and your arm is a lot less stable than when your arm is held tight to your body.
Your body is your tripod when you don't have one.
With your elbow sticking out, there is the potential for someone to walk past and knock your camera-holding arm and before you know it, your camera's on the floor. Otherwise, your wayward elbow could hit something, your arm could become more tired, more quickly...
All this means that, when shooting, you're more prone to camera shake and to me, this pose is not stable, secure or practical. All the things you need to be when shooting.
For a vertical portrait, I have always held my camera like this:
It came naturally to me, but I've since seen other photographers say they prefer holding their camera in the vertical position like this, too. In my opinion, it makes much more sense. Your body, your trunk, is firmer, more stable and therefore you're less inclined to experience camera shake and the resulting blurry images, because you haven't got the wayward, wobbly arm to worry about!
And to back my argument up, most photographers will tell you, when holding your camera horizontal/landscape, that you should have both elbows in to your body. This shouldn't change just because the orientation of your camera does.
Somewhat selfishly, cameras are generally made for right-handed people; The hand grip with shutter and important dials is all on the right hand side of your camera's body. So, your right hand should always, always be holding the camera grip and poised to press that shutter. This leaves your left hand to work the lens and change things like zoom and focus. This doesn't mean that your left elbow should be sticking out, though!
So, As a general rule, elbows in = sturdier body = more stable camera.
Now, I must add a disclaimer that this is my opinion and my personal preference. I have heard arguments for holding your camera the other way which have to do with the weight of the lens and whether you use a battery pack etc., this is just the way I do it.
How do you hold yours?