Good question Jack.
@Heie's article says it all, but I'd just emphasise a few points.
1. Stance matters. I hadn't appreciated how much until I read the article.
2. Grip matters. I do find it harder to get a steady position when shooting with the camera held vertically because, unless there is something to lean against, my right arm isn't braced.
3. Breathing matters. I try to press the shutter at the end of an exhale because I tend to press the shutter more smoothly (rather than stab at it) then.
4. Finding something to lean against makes a big difference. Alex (Heie) gives some practical examples. A tree trunk or branch, a door jamb, a car door or bonnet, a seat, a rock, a post or a rail can all help. If I can lock the fingers of my left hand on a door jamb I can drop the shutter speed quite a lot.
Of course a tripod or monopod is a big help, but I'm assuming we're talking about pure handheld.
One other point. I'd underline what @K-Three says. With your lens at 200mm, keep your shutter speed at 1/200th second or faster until you find you can reliably get steady shots at that speed.
Last edited by Des; 03-04-2016 at 02:33 PM.