The results of these attempts are amazing and it would seem that they took much longer to make. Usually in the process of making a film a great deal of time is taken to make decisions about what would be best in the production. There is no time to spend making decisions or discussing ideas. You have to go with whatever comes up at the moment.
As an experiment I would suggest that as an exercise you try Fly Filmmaking. Of course you may have to use your own camera and figure out how to do your own post-production as best you can, but it may be worth it. Any film school student could probably pull this one off. Use the school’s equipment loan program and you would also have a post facility available to you at not cost. This should challenge you and teach you to economize on the time and resources it takes to make a short film.