Mine actually is a mix of mission and smuggling. Missions can be incredibly fun and actually pays quite more than people would think--- profits are around 2 to 5 million per hour, if done correctly. More than enough to keep my chars alive.
My smuggling route also is rather safe, but it goes through California. Pays rather well, and it's quick.
Smuggling, occasionally trading lawfully with a friend. Shame my heart but when I need to actually make money to fund a project I stick to my backwater out of the way runs, rather than populating the houses. Don't mind getting pirated, don't like being pirated 9 times by gunboat fleets.
Running trade routes for Synth Foods is my primary source of income...and, well, my ONLY source of income for now. The backup computer I'm on is pretty finicky, and likes to overheat if I'm doing anything more complicated than flying and docking.
One complete trade circuit usually nets me about 8-12 mil (rough guesstimate, never really took the time to actually calculate it out), and takes maybe 20-30 minutes tops. This is, of course, variable and depends on how many times I get stopped and how many 'donations' I have to make.
Maybe some day, they'll see a hero is just a man who knowshe's free.
Trading lawfully, with a corporate trader - profits are low, but since I've given up any ambition to own anything larger than a GB, it'll be enough to keep my chars running and maybe for a new fighter now and then. I'm currently looking into bounty hunting as an alternative, since it seems to be much more fun than tedious F3-spamming and there's more interesting RP involved as well.