Making money in GTA:O is all about rationality and strategy. You should choose different approaches depend on your skill, level, playing style and time. Basically, it's choice between FUN/VARIETY and EFFECTIVENESS/ rationality. Ex: grinding RR 5x will get you more, than 2x RR and Trash talk + Mixed up with Coke in a Buzzard, but it's a nice thing to do for fun and also you will master flying skills.
Regardless of approach, there are common rules:
— When starting a session, sell a car like Baller, Felon or Felon GT. Don't waste too much time to find it, 3-5 mins max;
— If you're playing invite-only, grab Simeon vehicle. Otherwise, skip it. Risks are unacceptable: pain job $700 + getting killed $500 is almost 10% of the car price, also take your time into account;
— Gang attacks are only worth it you're under rank 50 without access to high-profile missions;
— Stay away from FR killing and police engaging. Want some kills? Play DM/ TDM and earn RP+ money for that.
— If you're low-level player, don't ignore invites to some high paying missions. Never ignore them. It's nice blast of XP+ cash
— Don't bother robbing a store. Even missions like Meth'd up will get you more for the same time/ effort;
— Always be rational, always consider your time. Set your priorities straight: more fun or more money. Don't chase bounties for half an hour and don't hide for lousy 9k for a 45 mins: it's question of 5 mins for mediocre skilled player to gain 2x more on RR;
— Races are paying nice, host your own if you're low player with catch-up and upgrades off, always turn traffic and cops on;
— From now on VERSUS mode like capture/ raid is paying extremely nice. Considering it's open for everybody without restrictions, play it IMMEDIATELY!
— If you're long-time gainer, invest in Buzzard. It will repay itself in more than 100 missions, but without it you'll spend much more for ammo in missions like Mixed up with coke, Trash talk, Los santos Connection, Crystal clear out I, II, III. In LS connection, don't spam rockets inside right upper corner of hangar and don't let others do it. It will fail the objective.
Information = power, so check out this topic:
Here our nice fellow described almost everything about money you can gain from jobs and cars.
I'm now level 161 with 6 mil in the bank LEGIT and here is my typical session: sell a Baller, host/ join RR for 2-3 times, play 2-3 races, 1-2 capture, Mixed up with coke and Trash talk x2, some free roam flying/ cruising. Outcome: more than $100,000 with a variety of activities. When Im'm in the mood, I can do RR/ Mixed up with coke and Trash talk SOLO for an hour for more than $200,000, but it's not as fun.
And last but not least: don't play survivals unless you need guns and you're low-level player. It's time consuming, but reward is a joke.
If you want a partner, add me, GT is in my signature. Doing RR, Mixed up with coke, Trash talk, Stock and Scares, Los santos connection, Base invaders. In LS connection and BI will provide helo support, in Stocks will provide also an extraction in Buzzard right from the dock.