In need of advice

[igcr]

Hi guys!

I need a little help to improve an specific kind of photography.

I've been shooting dancers and performers, in very low light situation.
I am currently using a Nikon D80 w/ 18-70mm lens 1:3.5 - 4.5G and a built-in flash. For now is all the equipment I have.

So here are the questions:
How can I improve this kind of photos? Should I use flash? Do I need to use the built- in flash in a different direction? Those are a very very fast subjects. I've been using 1600 ISO as the highest and the lowest aperture possible f3.5, the speed has been variable, some w/movement some others very dark and not using flash. honestly the low lights at the stage have been really cool to kill them with the flash! Oh, I forgot to mention that in all these cases I had the opportunity to be very close to the dancers so "long distance" is not a problem.

I attached some samples of "my not so cool pics", but I would like to get better images next time. There are important events coming up and i don't want to miss the opportunity to get better results!

Thank you so much in advance.

Idalia