In many ways, this is easier now than it used to be. There are many tutorials and classes for sewing, both online and in person. Check with your local fabric and craft stores. We always recommend going back to the established basics (books!!!) for sewing skills and technique reference. As with any art or craft, sewing skills are honed through repetition and practice and study of technique. If there is a specific technique you would like to learn, chances are good that there is a book about it.