Typical problem with this game. Sometimes it seems really random or lucky if you complete the level. Combat activities are fairly easy. You haven't tried crowd control or insurance fraud. For trafficking, ignore the dealer, focus on the gangs behind you unless the client make off and you have to kill him/her. If you are not a good shot. use bad weapons early save the shotguns for later. Snatch is only problematic if the pimp steals the hos back. If you have time, definitely change your ride once it starts smoking at later levels. Make sure it has 4 doors. Check the map and do some quick planning after every delivery.
The only diversion I can't complete is the last level of tow truck. I remember doing it once before when this game came out, before speedier CPUs made this game impossible to play until lately when it magically becomes playable again after doing updates on Windows 10. Got mad so I slowed the game to a crawl and finished the level. :D