Couple tips I've picked up for doing PvE in the DZ:
Use enemy mobs in subways/landmarks to your advantage -- constantly be weaving through to divert attention away from yourself and give yourself a fighting chance against rogue groups, esp. since I believe mobs scale in number depending on how many people are fighting it
Whenever calling for extraction, don't actually extract your items (or even reveal your position) until ~15s left on the clock (Rooftop and underground extraction points offer great hiding places w/ lines of sight to the rope)
Events (contamination events, supply drops, manhunts) all drop clean items that don't need to be extracted -- always nab one of these ASAP when you can. So does clearing a landmark.
Divtech containers don't need to be extracted either
Never travel through the main streets
A decent rule of thumb is -- if you can't solo a landmark with ease, you're probably not ready for DZ. Surviving as a solo or PVE player is all about knowing how to use the enemies of the world against anyone that might be chasing you.
WSP drops divtech for completing missions, and each time you craft/breakdown Damascus, you farm one Divtech so I usually just break down all redundant tools and weapons, and sell redundant gear (haven't found any good use for fabric).
