When it comes to getting better handling in Forza 5, there are a few things you can do. First and foremost, make sure your car is properly tuned. This means adjusting the camber, toe and ride height to match the specific track you're racing on. It's also important to keep your tires properly inflated - underinflated tires will cause your car to push (or understeer), while overinflated tires will make your car loose (or oversteer).
Another tip is to use the racing line as much as possible. The racing line is the quickest way around the track, and following it will help you maintain a good speed through corners. However, don't be afraid to experiment with different lines - sometimes a different line can be faster than the racing line. Finally, don't forget about weight transfer. As you brake and turn into a corner, weight will shift from the rear of the car to the front (and vice versa when accelerating out of a turn). This change in weight distribution can affect handling, so it's important to be aware of it and make adjustments accordingly.