Well, I just tried my first attempt at taking photos at a big game
(NOW WITH PHOTOS) Day 2 of Tippmann Challenge
I tried searching before hand but there all kinds of tips and some were pretty pricey for me so I just decided to learn on my own and "winged it" like I typically do

It was a risk, but one I fully assumed.
Equipment: I basically used what I had around me; a Nikon D60 with a Nikor 55-300mm lens. For the moment it does the job well enough.
Things I think I did right:
I tried to get close but not too close, tried to get a feel if either team is about to do a big advance and slowly walk away from any hot spots. I tried as hard as I could not not get in the way or be a nuisance to players on the field.
I walked slowly with the same gestures the refs were using to protect themselves. This seems to have helped a lot and I think reduce a lot of people accidentally shooting me.
Things I learned:
I learned I need more padding. I got shot up only twice all afternoon but it was nasty and I took a dozen close shots to my back.
I learned I should wear brighter clothing or something really unusual to stick out more. I should have put on a paintball vest in case of flyers and a backpack too.
I got lots of help from the refs in the field as they often tried to warn players on both sides who I was as I wondered between players.
I learned that if smoke bombs start going off nearby, to pull back since everyone will start shooting wildly into the smoke.
One real cool thing is I had some brief conversations with other photographers I met on the field and hope to get more knowledge that way.