Biggest thing to watch for is make sure you put the vanes back in the same way they came out. don't mix and match and turn them around. (shouldn't matter that much but if it has thousands of hours on it, then it might)
you'll need to make new seals, or buy new. (i've used paper coated in grease)
also, don't boil water if you want to pull high vacuums.
one thing i've done is make my own vacuum pump oil by pulling a vacuum on a gallon wine jug filled with synthetic motor oil, with a 1500 watt space heater under it, and a shell around it to direct the air flow around the glass. ended up pulling a vacuum on the oil for a few days, at about 70C. when you first turn the pump on you're going to get something equivalent to putting soap in a fountain, so don't fill the jug more than half way.