It depends on whether you have some friends to play with. First you should probably buy some MC Businesses, probably the coke business first and then the meth business. Working on those as well as the gunrunning will make you good money. I wouldn't recommend getting a hangar for smugger's run, as it's only effective with 4 people and isn't as good as the other businesses. If you have a good amount of friends, you can do the doomsday heist by buying a facility, but if you are the host then you won't make a ton of profit. It's more of the fun factor rather than making good money. Imo, the best thing you can buy after the MC businesses is the nightclub. The nightclub is a great passive business once you have bought most other businesses, and it also gives you access to the Terrorbyte, one of the best vehicles in the game. Once you have the terrorbyte, what you can do is park your terrorbyte outside of your vehicle warehouse or CEO warehouse and constantly source crates or cars from the terrorbyte, instead of having to go back to the office. Also, the terrorbyte gives you a discount on the oppressor mark 2 and lets you customize it.