If it's not your car or you're not yet used to it, try not to get too relaxed. That's my first principle when driving an unfamiliar car.

The cruise control is very useful on straight highways but can be used on long bending curves too provided alalay ka lang. Just make sure to keep watch of the time, your situational awareness, and your stress level. If you're too exhausted to drive, and you know it's a long one, pahinga ka na muna before you even set off. That cruise control button is just a temptation to doze off if you're not up to it.