Each command pod has a different level of torque it can apply. For example controlling a large, heavy rocket with a tiny probe core can make turning even a few degrees a chore. If you use RCS to assist turning, the placement of your thrusters can make all the difference. I always try to put port linear thrusters as far away from the center of mass as possible, usually with four symmetry. If that still isn't enough, I've had some success using pairs of small radial liquid engines instead of port linear thrusters and controlling them with action groups, but it can be overkill even with large heavy cruisers. Another cool tip is to use the physical time warp. The regular time warp puts the craft on rails, but if you hold alt while advancing time warp you can still apply torque and use engines. It can only go up to 4x speed, but for large craft or space stations, it can help a bunch.