Write a script. Film is a "show me" medium. Make certain the dialogue is not too wordy and focus on the action. The action in the script will detail what the audience sees. Without a good script, the following steps are useless.
Ask at least five of your most trusted, honest friends to read your story. Value their opinions and make relevant changes as needed. Again, it is imperative that the script be in top-notch shape and in the correct format. Almost 40 percent of submitted scripts are tossed in the trash because of incorrect formatting. You can find the proper script format at Scriptologist.
Create an accurate budget. Formulate what the film is going to cost to make. This is a very important step since studios want to know what their profit margin can be on the picture.
Build a marketing package. When submitting your idea, "eye candy" means everything. A small package with cover art, synopsis, budget outline and the script can make a difference.
Research your contacts. The film industry is a small community, but there is a line of guards that separate those on the outside from those on the inside. Some studios will not read a script unless it is submitted by an agent.
Befriend the producer's assistant. The producer's assistant has a direct line of communication to the decision makers. Be nice to them and build that relationship by phone or in person if you live in a city like Los Angeles or New York where film production companies are located.
Refuse to take "no" for an answer. When a studio or film company turns you down, don't scratch them off your list. Call them again in a few weeks.
Develop more ideas. The more ideas you have to pitch, the better your chance of success.
Trust your instincts. Hollywood has a way of recycling old concepts. Stay true to who you are and trust yourself as an artist.