Hi Chris,
I am no expert by a long shot but I have made many mistakes along the way. I have a few tips that might help.
Is it a small place? If so, are you permitted to use a flash? Normally, I don't use one because it really disturbs everyone. If you are allowed to use it though, it can't hurt. If you can use a flash, don't use it full blast because the whole atmostphere of the concert won't be the same in your photos.
If you aren't using a flash, which will probably be the case, you are going to want to boost up the ISO. Don't go too high! 800 is usually pretty high but if necessary, go higher. Try keeping your shutter speed no slower than 1/60, (I like 1/125), shoot wide open and adjust the ISO as needed. Just constantly meter and adjust the ISO because they may play with the lights too. Sometimes noise can not be helped and you will have to really boost the ISO but that can also be a cool shot. Just don't forget about it! I have forgotten my ISO often enough!
If you have a fast lens, that would be great so that you can save that precious light! At one point, I was using this little wee 50 mm 1.8 lens and it worked ok but I had to be really close to the action.
Don't use any filters. (Other than a protective lens)
If you have the time, try focussing manually. The AF gets funny in really low light.
Don't bother with a WB. The lights change often, so just shoot in RAW and adjust it later with your editing tools. (Any other time, I do set up my WB in the camera, except for this kind of thing.)
Other than that, just have a blast and move around a lot. Try mixing up your angles for cool shots. Include some of the crowd sometimes.
Don't delete any photos as you go! Wait until you get home. Some of the coolest concert shots look awful in the camera and end up being the most creative.
Have fun and share your shots with us.
Michele