Tell everyone you know that you made a film and would love it if they gave their support and told everyone they knew and so on and so on. Sometimes the most original films studied by film students are those that are passed on by word of mouth.
Post flyers online, around your town or city, and in schools or universities. Anywhere you think people frequent most is where you need to go to get the word out that you have made a film.
Show your film to the masses. With the flyers you have posted, include a day and time where you are going to screen your film and then afterward have a table set up where people can purchase copies of DVDs of your film.
Enter your film into film festivals so even more people can see it. The more people see what you have worked on, the better your chances that you will receive feedback on it. Any feedback is great feedback.
Send your film to networks and film industries. It may be a stretch but you have nothing to lose, except the cost of the DVD and maybe some of your time. Nevertheless, include with your film an introduction, the reasons why you decided to make the film and a quick, eye-catching synopsis.