People are having inconsistent experiences with these apps. I suppose that's partly down to their being version 1.0.
Having said that, there are some things that people have tried that work some of the time, so here goes.
Background
1. The watch uses the phone GPS to measure distance. If you walk or run withe the phone and watch, the watch will capture distance from the phone, and use it to estimate your stride length (factoring your height and age, I suppose). If you later go without the phone, the watch will attempt to estimates distance from your stride length multiplied by the number of steps.
2. It seems that the watch gets its step count from your arm swing via it internal accelerometer - for example, someone pushing a baby stroller, or holding the bars on a treadmill doesn't seem to record many of the steps.
3. The watch estimates your calorie burn from the above plus heart rate, age, weight etc
What's worked
- Doing several calibration walks/runs outdoors with both watch and phone and a very defined arm swing
- Unpairing and re-pairing the watch and phone
- Resetting the watch to factory and starting again
Having said all that, the mechanisms (hardware and software) do not yet seem to be 100% reliable and consistent, so you might find that none of this helps. If that's the case, a call to Apple support might help, but at least it'll help to register the extent of the issue