Movie Making Manual/You the Filmmaker/Growing as an Artist
You should read the excellent Irving Stone books about Van Gogh ("Lust for Life") and Michelangelo ("The Agony and the Ecstacy") what you will take from them is a new appreciation of the learning process and development of the artist. Both of these men accepted that it would take them years to get to grips with their media -- as not only did they want to master their mediums but both were revolutionizing them, taking both painting and sculpture into unexplored territories. The realisation both artists had was that not only would the development take time but that they also needed to live life along the way.
Peter Biskind (a close observer of filmmakers and filmmaking) said that, apart from a few exceptional cases (Welles, Tarantino), it takes at least five to ten years for a director to learn this art/craft. Sometimes it seems like we can be in a huge rush to get there: we make a couple of shorts and then want to make a feature with a big budget. Michelangelo spent years drawing, working with wax and clay before being trusted with expensive marble.
Go a bit easy on yourself if a few years into your film career you have not made something with which you are hugely pleased; this is a complex art form requiring many technical skills and a lot of knowledge and experience, and the tools are in the midst of a huge revolution. Expect things to take awhile.