We describe a prototype introductory physics laboratory designed to teach students some general intellectual skills widely useful in scientific work.  These skills include both basic skills (such as estimating quantities, determining errors, or applying useful measuring techniques) and higher-level skills (such as effectively describing experiments and flexibly adapting the resulting knowledge to different conditions).  The teaching methods emphasize the utility of organizing information in hierarchical and goal-directed fashion.  Furthermore, they strive to use an optimum combination of instruction means ("minilabs," more major "group labs," and integrated assessment devices) to achieve the desired ends.  A careful evaluation showed (i) that the prototype course is indeed quite successful in teaching the desired general intellectual skills, and  (ii) that these skills are ordinarily not acquired by students in traditional courses.  Students' attitudes toward the prototype course are also appreciably more positive.