Only way to understand positioning is to play lots of doubles.
Both players move as one, right and left, forwards and backwards.
Lob if you can't return away from the netperson, but lob DEEP and high.
Play your serves to the weak returning side, usually the backhand. No matter if it's more consistent than their big hitting side, you don't want to lose the point from the getgo.
Always volley low and up the middle, between the two players, service line deep unless you get a winner.