- Try shooting your subjects in simple circles first (or as much of a circle as you can walk around them), then follow up with fancier angles, provided that the new angles are close enough in position and angle to one of your other photos, or just take a photo between where you've already stood and your new dramatic angle if they're too different. Essentially you've got to show Photosynth how to get from any one of your photos to the next, using your camera.
I'm not certain if you've read the Photosynth Photography Guide, but it has more detail on things that should work and what probably won't work than I can describe here. Download it from this page: http://photosynth.net/howtosynth.aspx There's also a short video tutorial available there which is quite useful, but the Photography Guide has more detail.
The orbital technique is about the simplest that I can think of for new photosynthers. Try a few at different heights and distances and let me know how it goes.