Traditional Heist
The Heists are a very good methode to make money. The disadvantage you need after the first heist for all following traditional heists (not Doomsday heist) 4 players. To do this with randoms is at least at ps4 tedious.
At the beginning are the players who leave the mission instantly so you can search new players.
The next kind were the terminators who think they were imortal and got killed in the first 5 minutes.
Because of this expirience i recommend for beginners the fleeca heist. The Doomsday is a option too but need a higher level, more investements and equipement. To start the first heist you need a appartment with an office inside of the appartment. The cheapest is an Del Perro Heights and at least Player level 12. After this pruchase Lester will call you and invite you to the his office. After this you can start heists at your home office. If you like repeat the fleecajob later you have to call lester after the cooldown and press cancel haist and replay fleecajob. Don't do this if you allready paid for a another job as you will lose the money.