Need some comment on my open mic pictures

Last week I went to the school's open mic event, and did some shooting.
I was wondering what do you guys think about them.
It is pretty much the first time I am doing this,
I have been doing landscape for about 3 years, never really do events.
But come to realize landscape doesn't really have that big of a demand,
People are generally more interested in people, so I am trying this.
I would really like some comments on my pictures!
What I did good (if any), what I did wrong (be hard)...

I shoot these picture with: Canon 40D, 24-70mm, 580ex
But most of them I didn't use flash, because I want to keep the atmosphere,
the few that I did flash is because the performance stepped outside of the spot light.
I understand I should have try to talk to them, and suggest them stay in the range,
I will try to commuciate better with the performers next time, but for now here is what I got.
Please give me some feed back, really appreciated it.
You can be hard, I can take it! Thanks all!

1.

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Nice series. I like nos 2 and 4.

tonybear007 wrote in post #7523018
Nice series. I like nos 2 and 4.

Thank you very much