It depends on your ranks and your friendly factions.
In my case, I am taking on a stack of delivery missions (in a 200 ton python) as well as taking metal collection missions. I make about 10 mil credits a day.
I'm not trying for a billion or ten. I'm just enjoying what I do. (Which is why I'm shivering in my boots about the Thargoids. As well as being cold. 12 degrees C in my computer room. [knocked out])
If you want more than that then I can't help you. Though I did get 20 mil one day.
I play in solo and get quite a few combat bounties from NPCs trying to take my cargo. EG: One short trip saw me trash 1 Anaconda, 5 Diamondbacks, a Cobra 4, some Fed ships and at least one of the fancy ships with wings.
That was a good day, but I was held up from making trading money for a while.