The trick was to go into every mission, every time, with 100% health and armor. I didn't have too much trouble beating it and I didn't do any cheats nor vigilante or ambulance missions, nor date anyone except the two the game forces you to meet as part of the main story.

I've heard starting Vigilante in The Panopticon region makes it easier as you won't receive stars as often. Also, learn where the police bribes are so you can lower your wanted level (collect them if your wanted level is at 2 stars or more) You're going to want to get a police bike and a ton of MP5 ammo though (like 3,000+ rounds). Complete the Vigilante missions, as it will max out your armor bar.It's time consuming sure, but it's easier than Paramedic missions. Going to the gym regularly, running, cycling and also swimming will slightly boost your health bar.It's possible to do Paramedic missions in Los Santos, but it's much harder compared to AP & SF. If you complete level 12 you can max out your health bar. If you've completed 'The Green Sabre' try to complete the Paramedic missions in the town of Angel Pine or the city of San Fierro.There's a couple exploits for leveling up weapons, one is shooting the tire of a destroyed vehicle, the other is repeatedly shooting an invincible gsf member in the mission 'Reuniting the Families' (he's sitting down against the wall at the top of some stairs) You can do this by obviously shooting enemies or vehicles. You'll gain more accuracy, range, and other benefits that make combat a lot more manageable.

Gta san andreas weapon skill cheat