People ask “how did you get them to hold still?” all the time and the answer’s always the same. We didn’t. In our experience, there’s not much that works in getting dogs to hold still for their portraits. Treats dog work, calling their names is a crap-shoot and even though squeaky toys are just as likely to ruin things as they are to make things work.
All you can really do it is try to set things up and get a shot or two before things fall apart, and they almost always fall apart. I’ve worked as a street photographer and I’ve worked with models in a studio and even though the ratios of success to failure vary, there are always more failures than successes. That’s what makes photography so wonderful. It’s that those successes, when they come, make all the failures fade away so that all that matters is that one sweet shot.
Nothing replaces patience, keeping the energy level low and calm, and being ready so that when that one perfect shot comes along, you’re ready. A good analogy for life in general really.