* Start out upgrading character - Build Intelligence to 150, then build Sixth Sense and Chemistry to 150 as well.
* Next recruit dealers till you have about 2500 Drug Lords
* After you have 2500 drug lords, use your income to upgrade Transportation, and Laboratories
* As you upgrade Transportation and Laboratories, also get some thugs. Thugs are good to attack people that have lots of money, but no thugs to defend it.
* Be sure to upgrade thugs' stuff as well, but keep getting Dealers.