If you are getting shadows try moving the lights.

In portraits I would usually use three lights..two of them front lights and one used as a hair light.

I will try to explain the front lights.

From the camera point of view looking at the subject I would have one light at full power in front and to the right of the model.

I would have and the second light in front and to the left of the subject set at half power.

The hair light I would generally have been behind the model off to one side set at about half of 1/4 power.

This way any shadows would fall to the side of the model and not be seen in the photograph.

The hair light in England was called Rembrandt lighting...if you look at one of his paintings there is nearly always highlights on the hair.

In America it was called Hollywood lighting..well it would be wouldn't it :-)

This was pretty much a basic set up for a studio shot.

If I did this out side ( They got posh and called this environmental portraits ) then I would check the the reflected light from the subject ( in those days we used light meters ) but you can just do it by checking the camera readings and if there were shadows or the subject was back lit I would set my flash down about 1/2 power or even less. 

If I had an assistant with me I would use a white or gold reflector instead of the flash..was never a lover of flash.

I used to do some lovely photos using just window light.Sit the subject by a window and pose the model then shoot across the window so you only got the subject and not any burn out with the window or light outside.I would use a white reflector to lift any shadows on the model or maybe just let that side of the model fade to shadow.

Hope this may help in one way or another.
This may all be totally irrelavant to what you are aiming for but may help at times.
Eddie