Bring a tripod.
If you don't have a light, travel tripod, pick up a gorillapod slr-zoom or focus for cheap (i think it's like $30-50).
As far as interiors of casinos, I like the Bellagio conservatory for photos. At night, you can get a great view from pretty much anywhere, but i've heard suggestions of going to the top of the parking lot at the Bellagio for some good views. Also, if you'd also like to have a nice dinner, get out onto the patio of "Comme Ca" at the Cosmopolitan. There is a beautiful view of the center strip area (Paris, Ballys, PH). If you are good at taking photos through windows, I'd suggest the bar at the Mandarin Oriental (in City Center next to Aria). Great views of the strip from there as well (we were sitting on the southern side, so we could see excalibur, mgm grand, etc.)