Just try not to look like a Pap. I got harassed by Security on multiple occasions. If you take a tele lens (and you should), don't walk around with it zoomed out. I was there for a work function the first three days and being by myself defintely made me a target. When my wife joined me for the tail end of the trip I only got bothered once.
There's a lot going on there. A pair of zooms that cover 18-300mm did really well for me.
If you want to photograph the fireworks, you'll need to camp out early. All the best spots get taken quickly.
There's also a nightly laser show that's pretty cool but I lacked the photography prowess to snag any images worth sharing.
IIRC there are even some websites dedicated to photography at Disney\land\world - you might try to check them out.