In addition to what was already mentioned here: I would highly recommend a moist hide box (a tuppaware container with one hole cut in the side big enough for the snake to get in and out of. Cover it with contact paper if necessary to make it nice and dark inside. Fill it 1/3rd with sphagnum moss and mist it lightly with water every day.) I keep mine on the warm side of the terrarium. This REALLY helps my BP with his sheds... he has always shed in one perfect piece since I started using the moss box.
Also if you have lamps or Ceramic Heat Emitters inside the cage, you will need protective lamp cages to cover them so the snakes cannot burn themselves. Make sure that the cage is hanging securely so that the snake cannot climb inside and get fried (it HAS happened!

) Also make sure there are no sharp edges or spurs that the snake can get caught on (My Rainbow ripped open her side when she got caught on one of those.) You don't expect them to wrap themselves around hot lights, but they will. You don't expect them to wrap around metal cages protecting the lights, but they will... You want everything as safe as possible in your snake's home.
We changed the heating in Monty's cage from and undertank to a Ceramic Heat Emitter; it seems to work better for us.
You should have thermometers/hygrometers on both ends of the terrarium (warm end and cool end). We also have a thermometer/hygrometer with probe, plus we also have a thermostat timer: this one is outside connected to the Ceramic Heat Emitter. It is programmable to regulate high and low temps and down-regulate for the night time temperature range.
Other than that: hide boxes -- my BP loves the rubber knee pads from hardware store (turned upside down), untippable water bowl placed on the cool side or in the middle and branches for climbing. That's all I can think of that's really necessary. I tried putting in a waterfall for humidity, but that just got to be a hassle to clean and re-fill all the time (if you don't clean it often, dangerous bacteria can grow quickly). Now I just spray the cage daily with water when the humidity gets low.
I hope that helps a bit!