Go learn about Drug Labs: (Updating: Some info may not reflect conditions in 3.5)
Understand it's risks and rewards.
You need to bring them med-supplies so they can cook your widow. Agricultural supplies work too. Do not go empty handed or you probably can't buy anything. They buy both med-supplies and agricultural supplies at a premium, so just the trip out is profitable as well.
Jumptown Location https://www.reddit.com/r/starcitizen/comments/9y8sk4/33_live_jumptown_location_picture_goby/, you should be able to find it at night as it's the safest time to go, there are also Youtube videos. You start the run at Grim Hex.
Learn to avoid pirates, if someone is there when you arrive, just burn right on through. DO NOT LAND, with a full cargo of med-supplies on a cutlass you're out 78k aUEC, it's not
worth trusting someone to do the right thing.
If anyone is airborne in a non-trading vessel, they are probably going to kill you, so keep your afterburners on and get back to orbit as quickly as you can, then QT to safety.
If someone offers to not kill you in exchange for a few thousand credits, do it, this is a good deal.Running a Cutlass Black fully loaded with med supplies, then returning with Widow/Altruciatoxin is 35k profit
First sell Med-supplies, then buy as much widow as they will sell, then buy Altruciatoxin to fill your hold, then get the hell out of there and burn to orbit
Go to Ghex, get inside the safe zone and land/sell your stuff. You will have terminal sale problems, refer to the section above for handling this
When you have your hold empty, return to PO and repeat.
(repeated below in surviving pirate encounters) If you are coming into Jumptown, BURN at a high altitude and make a pass-over to ensure no one is nearby. The higher up you are, the harder you can burn. Any pirates lying in wait in ships will be radar detectable within 4-5km and will have a hard time catching you if you do a flyover at 800m/s.