Scaramouche, scaramouche will you do the fandango
Thunderbolt and lightning-very very frightening me
I don't really have any special techniques. I just make sure I get the parts I want in focus (which is usually the head of the figure). The really important thing is to have enough light. The amount and quality of light makes all the diffence. The other thing I do is shoot in RAW instead of JPG and make my adjustments in Adobe Lightroom or Photoshop. This allows me to correct the white balance, color, sharpness, etc. instead of the camera doing it for me. Getting the right white balance is crucial. So that's basically what I do. If you want more tips using flash ans strobes, just search for 'strobist' on google or flickr.
The second one, I'm not to sure if it turned out how I wanted. I think it is okay but I don't know if I could have done it better. I think I really wanted it to be against a black background and highlight his profile with light. I just could not do it with just the flash alone. I am really glad you like it though.