Part 1 of this series here.
When I want soft, directional light, I like to bounce light against walls behind me or to the side (I learned to bounce flash this way from www.planetneil.com). Usually the reflective surface of the walls is relatively large, producing soft light. Sometimes it's just not possible to bounce the flash this way, even indoors, for any number of reasons. The walls could be too far away, the walls could be too dark, or they have a strange color. Sometimes, bouncing off walls illuminates a larger area than I intend.
When bouncing from walls is not practical or desirable, I've gotten soft directional light from an H2U:
I was holding the h2u with my left hand approx. 45 degrees from the subject. I intended to use the h2u as key light, so I set shutter speed to sync speed, which maximizes the flash's ability to overpower the ambient. The flash was on i-TTL, triggered by CLS. Because this was on TTL, the way to increase the ratio of ambient to flash would have been to use a slower shutter speed, a higher ISO, or a larger aperture. Vice-versa to decrease ambient.
I also experimented with the h2u for quick setups without a light stand. In these examples, I
wanted to light from the side for a little drama. I just placed the umbrella roughly to side of the subject (not handheld anymore :) ). I liked the resulting effect of lighting from the side, but in retrospect I should have allowed more ambient light.
In the shots above, I also used the popup flash at -2 flash exposure compensation just to give a bit of lift to the shadows that would be caused by the light from the side.