Unlock the other businesses in GTA VCS

If you lack the smuggling business for example:
1) take the map and see who has a smuggling business (cholos, bikers, sharks)
2) attack ALL smuggling businesses
3) you will unlock the smuggling business (I know it's very annoying but it's funny, you'll see)

PS: you know which is the best business between racketeering, usury, prostitution

It's in the order of magnitude, it's prostitution.

Hi, you need to complete all the missions on the first island, then you should target rival businesses in drug trafficking, smuggling, and burglary in order to establish your own. ^^

Oh well, I found out how to do it.
For those interested, you have to tackle a certain number of businesses and after a while you unlock drugs and contraband, but for the last one you probably need to tackle even more because I haven't unlocked it yet.

If you're missing the smuggling business for example:
1) take the map and see who has a smuggling business (cholos, bikers, sharks)
2) attack ALL the smuggling businesses
3) you will have unlocked the smuggling business (I know it's very annoying but it's funny, you'll see)

PS: do you know which is the best business among extortion, loan sharking, and prostitution?

I did it but it doesn't work, I have the entire first city.