A basic edit suite should include:
-a second monitor
-3/4tb hard drive
-portable hard drives
-Good speakers and amplifier.
You don't need to spend a fortune on this for example you can by good quality screens and speakers second hand and look into refurbished goods.
2.Get a change of scenery.
Sometimes, working away from your studio can really help. Take a few days working in a different place. A great place to do this is a local library as it is a place you stay focused you have free access to wifi and you could stay there all afternoon if you needed to. On my recent documentary i edited while i was travelling, i found this worked well. With me getting up early spending a few focus hours in the morning working on it, then i would spend the rest of the day exploring and meeting people.
3. Edit as you go along.
It is a good idea to go through footage and interviews while you are filming to identify what works and where the gaps are. This will save you returning later.