I usually just try to loot as much as I can. Save up grenades of missiles to deal with tough opponents. Check your map; it shows you were the gas is going to move.
Every enemy has different stats/difficulty. Different weapons have different stats, EX: Bubblegum is high damage low accuracy, Pool toy is opposite.
The runs I win, I usually drop in an area with very few people, use UAVs to avoid scarier opponents, and try to avoid fights if possible.