Completion Level: 12
Reward: Health gets boosted to 150.
If you want to get to 100% completion in San Andreas, one of the most difficult tasks standing in your way will be the ambulance missions. These are somewhat similar to the taxi missions, in that you have to pick up fares and return them to the hospital, but although you have to complete fewer levels to complete the task, this is balanced against the fact that each level will require you to pick up an ever-greater number of passengers. At level one, you'll have one fare, at level two, two fares, and so on. The catch here is that your ambulance only has three seats, so starting at level four, you'll have to start making multiple drop-offs per level in order to get everyone back in one piece.
The complications here include the vehicle itself. Unlike a taxi, you can't bring an ambulance into a Pay N Spray, so you'll have to be incredibly careful with it while you drive around, since it'll need to last for the half-hour or more that you'll need to get all twelve levels out of the way. It's prone to tipping, as well, so you can't just blaze around turns, especially not when you're on an incline. In addition, you have to protect your passengers while you drive; if you subject them to too many collisions or big bumps, they'll die on you. Needless to say, slow and steady wins the race here.
Again, San Fierro is a bad place to try and finish off the Ambulance missions. Las Venturas is a better choice.
Completion Level: 12
Reward: Cash money.
In order to pimp, you have to enter a pimpmobile, of which there's only one variety: the Broadway. You can find one of these near the carwash a few blocks from Smoke's house, or near Madd Dogg's mansion in Los Santos, or in a variety of other locations. When you activate the pimping missions, you'll have to ferry your girls around to their stops and protect them from aggressive johns in exchange for a cut of the cash that they make.
Luckily, you only have two girls to deal with, so all you need to do is get them to their appointment before the clock runs out. After you drop off your first girl, you'll have an unlimited amount of time to reach the second girl, so hit the Pay N Spray if you need to restore your car's health.
After a few levels, the johns will start to get rough with your ladies, or attempt to leave without paying, so you'll need to whack them. You can get out of your ride for a few moments to use a weapon, or just perform a drive-by, if you wish.