I thought this is a good subject as i make LOTS every week - PC player here.
My tips for making money are:
Do all your dailies
Do everything that gets engineer badges
Get a 3000 badge crate and open it at this time and sell or use it
BUY 5000 fuel per week.
Find another player and do Frontier Defense Plastics or Electronic raids OUT OF REGION.
what this means is play in a dead timezone as then it will just be 2 players usually. I can normally get 55 plastics ( instead of 35 with 4 players) and 35 ( not 24) electronics per raid.
This system makes me around 2500 coins per week with premium subscription. I also max out on scrap every week.
What do others do?