Well, when quarantining animals you *should* have a separate room, but unfortunately this isn't always possible so you jsut have to compensate to the best of your abilities. Rules to live by when quarantining inthe same room:
1- keep animals as distanced in the room as possible
2- use papertowel (or newspaper) substrate so that it is easily changed and the snakes health can be monitored easily (bowel movements, mites, etc)
3- disinfect your hands between handling each animal (soap is ineffective as far as msot germs go, soap is for dirt; alcohol is for germs - i reccomend using a high potency alcohol spray on your hands and forearms followed by washing the antibacterial soap)
4- good idea to pretreat for mites, especially in these situations since mites carry disease and spread very quicky (up to 15 feet per day), this is not a must, but i would defintiely recommend it, because likely by the time you notice if it is a small infecstaion, it will probably be too late and have spread to your more established animals
5- never share any of the same equipment/supplies between animals such as sponges, dishes, etc.
I think I covered the basics, if I missed anything I will add to it