Film your documentary. At this stage, create the film you want. As an independent filmmaker, you have zero restraints, with the exception of a budget. Make it good and make it professional.
Research the various television stations that you wish to solicit your documentary to. Be sure that the topic of your documentary matches with the themes and beliefs of the television stations that will receive a copy of your work.
Show your documentary to the television stations that you have narrowed down as ones that will mesh with the themes of your documentary. Be sure to include cable and satellite television. Look into overseas markets, too.
Follow up with the stations that have seen your documentary. Often a station or cable outlet will receive so many solicitations that yours may get lost in the shuffle. Let the managers know who you are and what your work is. This may encourage them to look at your film again, or it may remind them of your work.
Certify that you have the legal right to distribute the documentary. When a television station accepts your documentary to air, it will require paperwork proving that you are the sole legal owner of the documentary. Make sure you have this information, otherwise, you will risk losing the chance to air your work.
After your film airs, search for a distributor so you can sell your work on DVD or via streaming services such as Hulu or Netflix.