Some conforming skirts have pull handles to help fit the model.  Also check the parameter dials for morph capabilities; this can closely match the pose of the model.  Poke throughs are very difficult to correct, sometimes scaling the outfit/model may give you the desired look or making body parts invisible under the outfit will give good results also.  Most of the time, outfits designed for a particular character will fit without problems and even morphing settings in both model and outfit usually fall into place.  The real problem occurs when there is specialized morphs that the clothing can't handle.  Magnets are a wonderful way to correct those problems.