It's easier if you put SAS in target-tracking mode and use it to keep your velocity vector pointed towards the target (by aligning the target and prograde cross

It's easier if you put SAS in target-tracking mode and use it to keep your velocity vector pointed towards the target (by aligning the target and prograde crosshairs). But yeah, once the distance gets into the triple digits it's definitely time to think about giving up on the docking attempt and just fixing your orbit. Note also that this effect is a lot stronger in KSP than in real life, since Kerbin has a much smaller radius than Earth and therefore orbital periods are shorter (assuming the same altitude).