This is probably the most relevant thing here, with only a t-shirt and jeans a survivor is extremely vulnerable to any attack, even adding a trenchcoat and a helmet is a great step up for surviving the first turn of the ambush.
Other than that your best bet is to just avoid getting ambushed, which is harder than it might sound.
Personally I always take the Quick trait, the extra bit of speed is super useful (Especially against turrets, as you sometimes step into that ‘extra’ turn, where you move twice before anything slower can react).
You can peek through windows with curtains without opening them, and generally look around corners using the ‘X’ key (Useful for spotting mi-go in the city before you get close).
Some traps make noise when they’re triggered, like bear traps or bubble wrap, these can help you wake up ‘before’ a bear is nomming your face off.
