Oh well, that's a bit hard because I skimmed through some of the storylines. You'll need to upgrade your storage and visit that often. Sell drugs as often as you can, and when yu visit storage to buy drugs to sell, a stranger will be there and he'll take you to his boss in the business district. Follow the story from there and you'll eventually meet the boss of the nightclub, fuck her brains out and be able to invest on the nightclubI ment to buy it.