There's a lot of tricks out there that you can use, to do some interesting creative things with your flash.
I'm going to tell you about one of my favorite ones. I use this a lot for when I'm photographing musicians. Something to me about, just the playing picture of a musician really doesn't convey the whole idea or the picture if you will.
So, my little trick I use with flashes and indoor photography. You need a really, really dark scenario. Often, I find when I'm photographing a band in a club or something it's really dark. So, what I do and it's a really neat trick. And, I encourage you to experiment with. You obviously have the camera on a manual setting. And, you're going to want to use your flash. You're going to use a mid-range aperture, something around five point six. But the trick comes in, in that you're using like a one or two second shutter speed. So, that the shutter is open for a long time.
What happens is, the shutter opens. The flash hits your subject. And, you get one solid image of your subject on the film. But, now you're shutter is still open for almost one or two seconds.
But, since it's such a really dim lit room and the flash is not going off again. It's not going to get over exposed. And, what I like to do then is to literally shake the camera around towards some small light sources. I mean, this can be as little as a cell phone or as big as a television. And, as long as you keep the camera moving it's going to pick up streams of light and seemingly wrap them around your subject.
And, again get out there and experiment. Because, it's a really really neat trick. There's endless tricks when it comes to flash. But, that one is my favorite. So, give it a try and see what you think.