Finally, to make it more interesting and more worthwhile I would grab a passenger mission to a tourist destination that is about 6K ly out. Make sure the passenger is easy going, not wanted anywhere etc.
You can easily make a few million from that mission *and* unlock Palin in one swipe.
The new deep core mining completely nullifies any other form of making money. I made several hauls of 250,000,000 credits each in void opal, which can be found in basically any pristine ice ringed planet (of which there are many).
To put that into perspective, I had 70,000,000 credits total (plus the value of my A-rated Clipper) going into this last update. Granted I haven't played in forever.
Steam + PSN: PHJF