What we've tried to do with our daughter (6) is to help by exposing her to a lot of things she is (or may be) interested in - dance, acrobatics, swimming, language, art, soccer, baseball, etc.  Some of those she did for quite a while (and still does), some not as long.  We try to enforce that she needs to finish out the current session of things that she's asked to do, despite how her feelings may have changed.  After all, kids' minds can change constantly.  If we've suggested it, we encourage her to follow through and make it to the end, but we don't push as hard.  What we care about most is that she has the opportunities in life to discover her strengths and weaknesses.