First up are you using the flash in Manual or ETTL mode? If you are using it in Manual then you will need to also have the camera in Manual to balance the settings. The easiest way to use the flash is in ETTL with the camera in AV or manual, set the aperture and shutter speed you want and then let the ETTL work out the flash power needed. As for the flash itself rather than firing it directly at the subject try bouncing it off the ceiling as this will give a more diffuse light and stop you from getting strong shadows behind the subject. In ETTL the camera/flash should compensate for the fact that you are bouncing it and adjust the power accordingly. This works best when you have normal height ceilings to bounce off, if it's too high then you will not get enough light bouncing back. For this or when shooting outside with fill flash I use something a bit like this -
http://www.amazon.co.uk/gp/product/B...MR2RK1G3W52HQV by altering the angle of it you can control how much flash is pushed forward.
How are you trying to fire the flash when it is off camera? I think to do so you would either need another Canon flash gun on camera, a speedlight transmitter or some radio triggers. If you are triggering the flash with a transmitter of another Canon flash then you will need to make sure you put the EX430 into slave mode and that it is on the same channel as the transmitter (if you are using a 7D you can trigger it with the inbuilt transmitter). Using radio triggers is one of the easiest ways to fire an off camera flash (OCF), you can either use expensive ones like the Pocket Wizards (silly money) or cheapie ones (I use RF603s which cost ~£35 for a set of three). The flash sits on one of them and another fits on the hotshoe of the camera. Doing it this way you need to use the flash in Manual, power can either be adjusted on the flash or by moving it closer to or further from the subject.
Hopefully some of that make some sense...