Flying is definitely the first challenge that players tend to meet. Just use autopilot. You can cancel the autopilot mid-flight, and you absolutely should cancel the autopilot if you start to see that a planet is getting in your way. Most people just fly with the autopilot, and that’s really my biggest advice.
If you really insist on flying manual, don’t treat it like driving a car. Spaceships (both real and in-game) drift most of the time. You want to get up to speed (400 m/s is a good top speed most of the time) and then drift the rest of the way to your destination. Do you see the white dotted arrows coming out from the planet that you’re targeting? You want to get those arrows to be as short as possible. If the arrows are visible, that means you’re not lined up with the planet and you’ll miss the planet