Mostly it's intuitive. Practice is essential. Here are some common tips: -Let your trajectory either lead or fall short of your target, depending on your heading and the rotation of the planet/ moon. This is because as you're falling the planet may rotate under you, taking the target with it. Also applies for landing in atmosphere, as the map trajectory doesn't account for air resistance and you'll need space to slow. -Some people like to come to a dead stop (no horizontal speed) above their target and then fall onto it. This typically uses a lot of fuel. -Target markers can be helpful.