I found the best way to get cash was combat missions, once I'd got a bigger ship mining became more profitable as I could store more in the hold as I mined (and as my mining skill improved I did it faster).
Tip 1:
Goto and asteroid field, fly 15km past it, set a waypoint there
Warp back to the station, go 15km past it, set a waypoint there
Now between those two points you jump straight into the asteroid field, mine, jump to station and dock immediately. It also means you can sometimes jump in, mine and get out before the pirates turn up if you don't fancy fighting.
Tip 2:
Find the right place to sell, I found in the end the unrefined ore was for some reason netting me more money than the refined result and the difference was quite large.
Hearing people talk about it does make me have pangs for it, but I found combat just so amazingly dull and mining was just a way to relaxingly pass the time. I think if the controls were not all point/click I'd feel more involved with it. If enough people appeared to make a Clan UK company I might pop back for a bit to say hi and have some fun, but I'll watch and see how things turn out if you do get something started or regular trips organised.
Course I'd probably need to spend the first day back moving all my bits and ships to where we would be based (travel while realistic is dull when going a distance, which I guess makes it all the more realistic)