For Civ:
I'd say the best place to start on Altis Life would be to start off doing some small time runs (i.e peaches or apples) to get your player economy up. These runs can be found in all of the major cities and only require a small vehicle like an offroad or even a quadbike. To be honest if you're doing runs in Kavala/Sydney you really need a gun to defend yourself. I'd start in Athria or Pygros to keep away from bein robbed, then move over to Kavala if you want.
After you've done that, go save up for a helicopter (or truck) and licence training for a larger run such as copper or iron. Do a few of those then move to illegal runs, just be careful of Cops and other gangs protecting their drug fields. Also go get a rebel/contractor/cartel licence so you can get some better gear.
For Cop:
Jump on as a pubslot officer and learn how to be a cop. You can make a lot of money by being a cop (same with ems) as your paycheck is $5000 compared the $1000 of civ. Also you get cheap weapons and gear, but you have to adhere to their protocols (like not give gear away). To become white listed you need minimum 15hrs as a pubslot cop (forgot to say but you need to be on teamspeak (ts.straya.life) at all times) and submit an application.
For Medic:
Pretty much the same as cop, but you don't get weapons. You get paid the same (I do believe so) and you get $10,000 per revive you get. Also they have their own rule set that you have to follow and same with cop you have to be on teamspeak at all times.
I'll let you decide but personally I find cop or medic as a good option to start off with, as you pretty much earn a lot of money in a short timeframe with a bit of effort. Also read the rules as well so you don't break any accidentally. Have fun and welcome to the community!