Identify the entity's species. In order to properly prepare yourself for an encounter, it is best to know what exactly you are up against. For instance, proper defense against The Faux involves surrounding yourself with known companions who are not suspected entities, whereas with a Mould, more people creates more danger as they are capable of possessing anyone on a dime. Please see the footnotes below for more information on specific entities.
If possible, stock up. Entity encounters can be an incredibly long, grueling experience. If possible, collect whatever weapons, food, and water you can reasonably carry on your person in case you become unable to reach a store or other sources of necessities in the future. Water is most essential if you feel you need to be on the run, but any sort of weapon is better than none at all, even if it does not help you in the end.
Do not panic. They can smell your fear. You need to keep a strong, healthy mind in order to survive an entity. They prey on your weakness and timid behavior, and it is imperitive that they know you will take them seriously if they approach. For some weaker entities, this may be enough to deter them. Do not count on it.
Do not stay in your home. Regardless of if you are hunkering down or going on the move, you do not want to stay in your own living space, as it is the most likely location an entity will find you in. Consider a hotel, communal housing, or the house of a friend you do not truly value. They might forgive you.
Pray to your God.
Surviving An Encounter With...
A Mould: With a Mould, it is important that you stay on the move. Moulds are persistent, one-note hunters, and if you have crossed one, you have already made a grave mistake. If it is simply predating on you for food, it is more likely that you will survive. You must give them a challenge; make it as difficult as possible to hunt you down, and make them consider an easier target. Do not hunker down. You are only making it easy for them.
The Faux: Employ mirrors or other reflective surfaces for a potential chance to see where its bodyless form is. However, this will likely only prolong your fear. If you are being stalked by a Faux who intends to use your body, you will not survive.
If trying to escape a Faux who already has a body, and is intending to predate on you, it is most important to put yourself into large crowds or groups, and to blend in as much as possible. Like with Moulds, it is important to simply make yourself not worth the hassle, and to find someone else who will be easier and less prepared.
Interlopers: As interlopers are particularly unpredictable, little can be said in this particular regard. However, the most common survival strategy is to hunker down in a heavily fortified building, such as a highly fortified home or bunker. As interlopers have their own bodies, and often live as humans socially, you may even want to call the police. Use of weapons on interlopers can be more effective than using it on other entities, though do not count on it killing the attacker. If you manage to knock it down, run until you are confident it no longer knows where you are.
Spirates: Similarly to The Faux, you should stay in very large crowds and draw little attention to yourself. If you are in a precarious, near-attack situation, such as a spirate already being inside your home, it is also possible that playing dead may deter an attacking spirate, as they will not be able to assimilate the dead.