IK is usually the fastest/easiest way to adjust poses.

step 1: please, for the love of god, ground the feet on the floor. my biggest pet peeve in poses is when the figures are floating 2" in the air.

step 2: turn on IK for the feet.

now you can twist the hip group to cock the hips, you can grab a foot and move it to the side or front/back, etc. if you raise/lower the hip youll bend or straighten the knees, etc.

the same can be done (to a far limited degree) with the hands. say you have a pose that has both of a characters hands on their hips, you can turn on IK for both hands and twist/bend the chest/abdomen a bit and adjust the pose. this is far easier than with IK off, and then having to sit there and retweak the hands/fingers all over again.

you can also use it to fix 'balance' in some poses. for example a standing pose where the figure is unnaturally out of balance to one side or another, just turn on IK for the legs, grab the hip, and Z or X translate it. without IK youd have to rotate the hip, and then go and bend/side-side the legs and try to get them grounded again.

no its not perfect, and no its not the answer to every posing problem -- sometimes the limbs will pretzel up on you. big deal, thats what CTRL-Z is for.