Compared to everyone else, I haven't done much, but I have owned this game for a just couple of days and haven't really had time to play much. Today, in career, without upgrading my tracking station, I put a Kerbal into a stable orbit by eye, deorbited him safely and feel pretty darned good about. It took a handful of aborted attempts, but it's all good. As many people have said here, it's all in reading the navball and watching your fuel. I will be glad when I can upgrade my tracking station and get maneuver nodes, though.